Materiały źródłowe

• #1 Vitamin Deficiency Anemia: Symptoms & Causes

  https://my.clevelandclinic.org/health/diseases/17732-vitamin-deficiency-anemia

  Vitamin deficiency anemia is a condition that develops when you have low levels of vitamin B12 or B9 (folate). In this type of anemia, your body doesn’t produce enough healthy red blood cells. […] Your healthcare provider can use blood tests to diagnose vitamin deficiency anemia. This blood test may evaluate: Folate and vitamin B12 levels. Red blood cell count and appearance. […] Treatment for vitamin deficiency anemia aims to increase your levels of the vitamin you’re lacking. Your provider will determine the best dosage and type of treatment. […] If you have suspected vitamin deficiency anemia, you may want to ask your healthcare provider: What tests do I need to diagnose vitamin deficiency anemia? […] Vitamin deficiency anemia is when your body doesn’t make enough healthy red blood cells. It commonly develops because of a deficiency in vitamins B12 or B9. Treatment for this type of anemia focuses on restoring your B12 or B9 levels.

• #2 Vitamin B12 & folate anaemia | NHS inform

  https://www.nhsinform.scot/illnesses-and-conditions/nutritional/vitamin-b12-or-folate-deficiency-anaemia/

  Vitamin B12 or folate deficiency anaemia occurs when a lack of vitamin B12 or folate causes the body to produce abnormally large red blood cells that cant function properly. […] See your GP if you think you may have a vitamin B12 or folate deficiency. These conditions can often be diagnosed based on your symptoms and the results of a blood test. […] A diagnosis of vitamin B12 or folate deficiency anaemia can often be made by your GP based on your symptoms and the results of blood tests. […] Different types of blood tests can be carried out to help identify people with a possible vitamin B12 or folate deficiency. These tests check: whether you have a lower level of haemoglobin (a substance that transports oxygen) than normal, whether your red blood cells are larger than normal, the level of vitamin B12 in your blood, the level of folate in your blood. […] If your symptoms and blood test results suggest a vitamin B12 or folate deficiency, your GP may arrange further tests. If the cause can be identified, it will help to determine the most appropriate treatment.

• #3 Vitamin B12 Deficiency – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK441923/

  Vitamin B12 deficiency can lead to hematologic and neurological symptoms. […] This activity describes the evaluation and management of vitamin B12 deficiency and highlights the role of the interprofessional team in improving care for affected patients. […] A thorough evaluation of vitamin B12 deficiency should include a complete history and physical with an increased emphasis on gastrointestinal (GI) and neurologic findings. […] In patients with suspected B12 deficiency, initial lab tests should include a complete blood count (CBC) with a peripheral smear and serum B12 and folate levels. […] After a B12 deficiency confirmation, the etiology must be addressed. […] Treatment of vitamin B12 deficiency involves repletion with B12. […] For patients who are promptly treated with vitamin B12, the prognosis is good. […] The ideal way to manage the disorder is with an interprofessional team that includes a primary clinician, gastroenterologist, neurologist, surgeon, pharmacist, dietitian, and a nurse.

• #4 Vitamin B12 deficiency – Symptoms, diagnosis and treatment | BMJ Best Practice US

  https://bestpractice.bmj.com/topics/en-us/822

  Other diagnostic factors include paresthesias, vegan and strict vegetarian diet, chronic gastrointestinal disease (e.g., Crohn disease or celiac disease), medication (proton-pump inhibitors, H2 receptor antagonists, metformin, anticonvulsants), ataxia, decreased vibration sense, positive Romberg test, pallor, petechiae, glossitis, angular cheilitis, and cognitive impairment. […] 1st tests to order include CBC, peripheral blood smear, serum vitamin B12, and reticulocyte count. […] Tests to consider include methylmalonic acid (MMA), homocysteine, holotranscobalamin (hTC), anti-intrinsic factor antibody (anti-IFAB), antiparietal cell (APC) antibody, and serum gastrin (fasting).

• #4 Vitamin B12 deficiency – Symptoms, diagnosis and treatment | BMJ Best Practice US

  https://bestpractice.bmj.com/topics/en-us/822

  Vitamin B12 (cobalamin) deficiency classically presents with megaloblastic anemia, but can also present with neurologic and neuropsychiatric complaints. […] Early diagnosis is critical in preventing and halting the progression of neurologic disorders such as peripheral neuropathy, subacute combined degeneration of the spinal cord, and dementia. […] Methylmalonic acid and homocysteine levels may help to diagnose vitamin B12 deficiency at an early, asymptomatic state. […] Cause of vitamin B12 deficiency should be searched for once a diagnosis is confirmed. […] Vitamin B12 level 350 picograms/mL does not exclude vitamin B12 deficiency, particularly if pernicious anemia is suspected. […] Key diagnostic factors include old age and history of gastric surgery (gastrectomy, or bypass for obesity).

• #5 Vitamin B12 Deficiency Anemia – UF Health

  https://ufhealth.org/conditions-and-treatments/vitamin-b12-deficiency-anemia

  Vitamin B12 deficiency anemia is a low red blood cell count due to a lack (deficiency) of vitamin B12. […] The health care provider will perform a physical exam. This may reveal problems with your reflexes. […] Tests that may be done include: Complete blood count (CBC), Reticulocyte count, Lactate dehydrogenase (LDH) level, Serum bilirubin level, Vitamin B12 level, Methylmalonic acid (MMA) level, Serum homocysteine level (amino acid found in blood). […] Treatment depends on the cause of B12 deficiency anemia. […] The goal of treatment is to increase your vitamin B12 level. […] Long-term vitamin B12 deficiency can cause nerve damage. This may be permanent if you do not start treatment within 6 months of when your symptoms begin. […] Early diagnosis and prompt treatment can reduce or prevent complications related to a low vitamin B12 level.

• #6

  https://www.nhs.uk/conditions/vitamin-b12-or-folate-deficiency-anaemia/diagnosis/

  A diagnosis of vitamin B12 or folate deficiency anaemia can often be made by a GP based on your symptoms and the results of blood tests. […] Different types of blood tests can be carried out to help identify people with a possible vitamin B12 or folate deficiency. […] It’s also important for your symptoms to be taken into account when a diagnosis is made. […] If your symptoms and blood test results suggest a vitamin B12 or folate deficiency, your GP may arrange further tests. […] Tests for pernicious anaemia are not always conclusive, but can often give your GP a good idea of whether you have the condition. […] You may be referred to a specialist for further tests or treatment.

• #7

• #8 Vitamin Deficiency Anemia – Blood Disorders – Merck Manual Consumer Version

  https://www.merckmanuals.com/home/blood-disorders/anemia/vitamin-deficiency-anemia

  Vitamin deficiency anemia results from low or depleted levels of vitamin B12 or folate (folic acid). […] Blood tests can detect abnormal cells that indicate vitamin deficiency anemia. […] Once blood tests show a person has anemia, tests are done to determine if a deficiency of vitamin B12 or folate is the cause. Anemia due to vitamin B12 or folate deficiency is suspected when large (macrocytic) red blood cells and multilobed (hypersegmented) neutrophils (a type of white blood cell) are seen in a blood sample that is examined under a microscope. The blood levels of vitamin B12 and folate are measured, and other tests may be done to determine the cause of the vitamin B12 deficiency.

• #9 Case Study: Vitamin B12 Deficiency – ASCLS

  https://ascls.org/case-study-vitamin-b12-deficiency/

  Based on the clinical presentation and laboratory findings, a diagnosis of psychomotor regression due to B12 deficiency was made. […] Common diagnostic lab tests for B12 deficiency typically begin with serum B12 measurement and a complete blood count (CBC). Low B12 levels and evidence of megaloblastic anemia (decreased RBC, Hgb, Hct, WBC, platelet count, increased MCV, large oval RBCs and hypersegmented neutrophils) indicate B12 deficiency. […] Diagnosis of B12 deficiency can be complicated since symptoms may be vague and lab test results can be equivocal.

• #10 Vitamin B12 deficiency – Wikipedia

  https://en.wikipedia.org/wiki/Vitamin_B12_deficiency

  Blood tests may show low levels of vitamin B12, elevated levels of methylmalonic acid or homocysteine, and a routine complete blood counts may shows anemia with an elevated mean cell volume. […] The presence of antibodies to gastric parietal cells and intrinsic factor may indicate pernicious anemia. […] Deficiency can develop without anemia or within normal vitamin B12 levels, leading to a methylmalonic acid or homocysteine assay. […] In some cases, a peripheral blood smear may be used; which may allow to show macrocytes and hypersegmented polymorphonuclear leukocytes. […] Neuropsychiatric symptoms can precede hematological signs and are often the presenting manifestation of B12 deficiency.

• #10 Vitamin B12 deficiency – Wikipedia

  https://en.wikipedia.org/wiki/Vitamin_B12_deficiency

  Vitamin B12 deficiency is the medical condition in which the blood and tissue have a lower than normal level of vitamin B12. […] Diagnosis is typically based on blood levels of vitamin B12 below 148185 pmol/L (200 to 250 pg/mL) in adults. […] Diagnosis is not always straightforward as serum levels can be falsely high or normal. […] Elevated methylmalonic acid levels may also indicate a deficiency. […] Individuals with low or marginal values of vitamin B12 in the range of 148221 pmol/L (200300 pg/mL) may not have classic neurological or hematological signs or symptoms. […] A diagnosis of vitamin B12 deficiency is determined by blood levels lower than 200 or 250 picograms per ml (148 or 185 picomoles per liter). […] Measurement of blood methylmalonic acid (MMA), a vitamin B12-associated metabolite, is a commonly used biomarker.

• #11 Severe megaloblastic anemia: Vitamin deficiency and other causes | Cleveland Clinic Journal of Medicine

  https://www.ccjm.org/content/87/3/153

  Vitamin B12 deficiency causes hematologic and neuropsychiatric manifestations that may occur together or independently. […] Megaloblastic anemia due to folate deficiency and other causes shares the same hematologic manifestations as vitamin B12 deficiency but lacks the neurologic features. […] The complete blood cell count reveals anemia that is generally macrocytic (MCV 100 fL). […] Hypersegmented neutrophils in the setting of macrocytic anemia are considered specific for megaloblastic anemia and are rarely seen in other diseases. […] Specific laboratory evaluation for vitamin B12 deficiency begins with total serum cobalamin levels. […] Vitamin B12 levels lower than 200 g/mL are highly suggestive of deficiency, although false-positive and false-negative results can happen. […] For borderline cobalamin levels (200-400 g/mL), additional laboratory testing, including serum methylmalonic acid and serum homocysteine levels, should be performed.

• #11 Severe megaloblastic anemia: Vitamin deficiency and other causes | Cleveland Clinic Journal of Medicine

  https://www.ccjm.org/content/87/3/153

  The combination of these 2 tests significantly increases their diagnostic performance, with 73% sensitivity and 100% specificity in pernicious anemia. […] After establishing the diagnosis, treatment should be initiated promptly. […] Treatment is specific to the underlying condition and usually involves supplementing the deficient vitamin. […] With either vitamin B12 or folate supplementation, the rapid bone marrow response can push borderline iron stores into deficiency, so patients should be monitored for iron and provided with supplementation as needed. […] Megaloblastic anemia secondary to folate deficiency is generally treated with oral folate, as it is most often caused by dietary deficiency rather than malabsorption. […] Prompt treatment is particularly important for patients with vitamin B12 deficiency in order to prevent neurologic symptoms from becoming permanent.

• #11 Severe megaloblastic anemia: Vitamin deficiency and other causes | Cleveland Clinic Journal of Medicine

  https://www.ccjm.org/content/87/3/153

  Megaloblastic anemia can be diagnosed based on characteristic morphologic and laboratory findings. […] Therapy involves treating the underlying cause, eg, with vitamin supplementation in cases of deficiency, or with discontinuation of a suspected medication. […] Both vitamin deficiencies cause hematologic signs and symptoms of anemia; vitamin B12 deficiency also causes neurologic symptoms. […] Oral supplementation is available for both vitamin deficiencies; intramuscular vitamin B12 supplementation should be used in cases involving severe neurologic symptoms or gastric or bowel resection. […] Not all megaloblastic anemias result from vitamin deficiency, but most do. […] Determining the underlying cause and initiating prompt treatment are critical, as prognosis and management differ among the various conditions.

• #11 Severe megaloblastic anemia: Vitamin deficiency and other causes | Cleveland Clinic Journal of Medicine

  https://www.ccjm.org/content/87/3/153

  Vitamin B12 can be supplemented in different forms; noted preferences vary worldwide: cyanocobalamin in the United States, hydroxycobalamin in Europe, and methylcobalamin in Asia. […] Mild vitamin B12 deficiency should be treated with oral dosing, reserving intramuscular dosing for patients with significant neurologic symptoms, adherence issues, or extensive gastric or bowel resections.

• #12 Diagnosis of Pernicious Anaemia | Pernicious Anaemia Society

  https://pernicious-anaemia-society.org/diagnosis/

  From the very beginning this charity has been made aware that there are serious problems with patients receiving an early diagnosis that will explain their symptoms. The problem of getting an accurate and quick diagnosis were the subject of many discussions on social media and on our online forum and its extent became clear when the results of our survey 1 were published. We asked over a 1,000 of our members whether they were given an initial false diagnosis and how long they had experienced symptoms before being diagnosed. 48% were initially wrongly diagnosed as having some other problem. […] There are several reasons why there are problems with patients getting quickly and accurately diagnosed. […] The problems with diagnosing Pernicious Anaemia begin with the issues surrounding diagnosing B12 Deficiency; these are outlined below: There is no consensus of what constitutes a vitamin B12 deficiency. Some commentators believe that the current reference level used to determine a deficiency is too low and needs to be raised. Doctors are not looking for B12 deficiency. That’s why it’s important that you ask your doctor to check your B12 levels. There are serious shortcomings with the current test used to determine B12 status in patients. The current test, the Combined Binding Luminescence Test is giving false high results in between 22 and 35% of patients (depending on the manufacturer of the test machine). If your test results come back as normal or borderline you may want to ask your doctor for a therapeutic trial of B12 injections to judge whether you feel better. Different laboratories set different thresholds to determine a deficiency. This means that in one area of the country your test results might indicate a deficiency whereas in another area you wouldn’t be considered to be deficient. This makes diagnosing any deficiency dependent on your postcode. There is an even greyer area with sub-clinical deficiency a deficiency even though the patient’s B12 status is above the normal threshold for determining any deficiency. B12 status is not part of the Full Blood Count that is routinely investigated by doctors. Instead most doctors will rely on enlarged red blood cells (megaloblasts) as being an indicator of low B12. However, only around 60% of patients with a B12 deficiency will have enlarged red blood cells (macrocytosis), therefore a normal MCV does not rule out a B12 deficiency. Neurological symptoms due to cobalamin deficiency may occur in the presence of a normal MCV. Ask for your B12 to be tested if your full blood count doesn’t show any signs of enlarged red blood cells.

• #12 Diagnosis of Pernicious Anaemia | Pernicious Anaemia Society

  https://pernicious-anaemia-society.org/diagnosis/

  Test serum B12 or active B12 as the initial test for suspected vitamin B12 deficiency unless the test needs to be done during pregnancy, then test Active B12. The clinical picture is the most important factor in assessing the significance of test results assessing cobalamin status since there is no gold standard test to define deficiency. Do not delay vitamin B12 replacement while waiting for the test results of people with suspected megaloblastic anaemia and neurological symptoms, especially symptoms related to sub-acute combined degeneration of the spinal cord. Definitive cut-off points to define clinical and subclinical deficiency states are not possible, given the variety of methodologies used and technical issues, and local reference ranges should be established. In the presence of discordance between the test result and strong clinical features of deficiency, treatment should not be delayed to avoid neurological impairment.

• #13 Vitamin deficiency anemia – Diagnosis & treatment – Mayo Clinic

  https://www.mayoclinic.org/diseases-conditions/vitamin-deficiency-anemia/diagnosis-treatment/drc-20355031

  To help diagnose vitamin deficiency anemias, you might have blood tests that check for: […] The amount of vitamin B-12 and folate in the blood […] The presence of antibodies to intrinsic factor, which indicates pernicious anemia.

• #14 Vitamin B12 Deficiency – Nutritional Disorders – Merck Manual Professional Edition

  https://www.merckmanuals.com/professional/nutritional-disorders/vitamin-deficiency-dependency-and-toxicity/vitamin-b12-deficiency

  Dietary vitamin B12 deficiency usually results from inadequate absorption, but deficiency can develop in vegans who do not take vitamin supplements. […] Diagnosis is usually made by measuring serum vitamin B12 levels. […] Diagnosis of vitamin B12 deficiency is based on CBC and vitamin B12 and folate levels. […] A vitamin B12 level 200 pg/mL (145 pmol/L) indicates vitamin B12 deficiency. […] When clinical judgment suggests vitamin B12 deficiency but the vitamin B12 level is low-normal (200 to 350 pg/mL [145 to 260 pmol/L]) or hematologic indexes are normal, other tests can be done. […] The Schilling test is useful only if diagnosing intrinsic factor deficiency is important, as in classic pernicious anemia. […] The Schilling test measures absorption of free radiolabeled vitamin B12.

• #14 Vitamin B12 Deficiency – Nutritional Disorders – Merck Manual Professional Edition

  https://www.merckmanuals.com/professional/nutritional-disorders/vitamin-deficiency-dependency-and-toxicity/vitamin-b12-deficiency

  If absorption is normal, 9% of the dose given appears in the urine. […] Reduced urinary excretion (5% if kidney function is normal) indicates inadequate vitamin B12 absorption. […] After vitamin B12 deficiency is diagnosed, additional tests (eg, Schilling test) may be indicated for young and middle-age adults but usually not for older adults.

• #15 Vitamin B12 Deficiency: Signs, Causes and Treatments | Ada

  https://ada.com/conditions/vitamin-b12-deficiency/

  A doctor will typically take the persons medical history and perform a physical examination. […] Some people experience symptoms of vitamin B12 deficiency despite their blood tests indicating normal levels. […] Sometimes blood tests will show normal serum levels of vitamin B12, but a person may experience symptoms and complications related to a deficiency. This can be known as functional vitamin B12 deficiency. […] Treatment will depend on the reasons for the vitamin B12 deficiency. In most cases, having injections or taking a prescribed oral supplement will be sufficient to treat the condition. […] Follow-up blood tests will generally be requested one to three months after starting treatment, to check that vitamin B12 levels have returned to normal.

• #16 Testing for Pernicious Anaemia | Pernicious Anaemia Society

  https://pernicious-anaemia-society.org/articles/testing-for-pernicious-anaemia/

  Although the threshold figures will vary from laboratory to laboratory because different laboratories use analytical machines made by different manufacturers the typical cut-off value used to define B12 deficiency is around 148 pmol/L (200 pg/mL) and for a growing number of scientists this is far too low and, if patients are showing symptoms of B12 deficiency yet their blood result shows their B12 to be above 148 pmol/L the patient should be treated. […] Definitive cut-off points to define clinical and subclinical deficiency states are not possible, given the variety of methodologies used and technical issues, and local reference ranges should be established. […] The NICE Guideline states: Less than 180 ng/l (133 pmol/l) : Confirmed vitamin B12 deficiency Between 180 and 350 ng/l (133 and 258 pmol/l) : Indeterminate test result possible vitamin B12 deficiency. Consider further testing in patients with symptoms.

• #16 Testing for Pernicious Anaemia | Pernicious Anaemia Society

  https://pernicious-anaemia-society.org/articles/testing-for-pernicious-anaemia/

  This is the test used to find out if the patient has Pernicious Anaemia. […] However the test has a low sensitivity (50-70%) which means that a negative result does not rule out Pernicious Anaemia. […] A negative test result does not rule out the presence of Pernicious Anaemia. […] When a patients tests negative for antibodies, but Pernicious Anaemia is likely, this test can be used. […] If you are concerned about any part of your blood results you should discuss this with your doctor. However, as we have seen above, some of the tests are seriously flawed.

• #16 Testing for Pernicious Anaemia | Pernicious Anaemia Society

  https://pernicious-anaemia-society.org/articles/testing-for-pernicious-anaemia/

  As soon as the Pernicious Anaemia Society was formed it became obvious that some, though not all patients faced a long journey in being diagnosed quickly and accurately. […] And it is only recently that research papers have been published that show that one of the reasons is because the current tests used to diagnose vitamin B12 deficiency in general and whether that deficiency is caused by Pernicious Anaemia are seriously flawed. […] Despite studies consistently demonstrating that no single biomarker of B12 status exhibits the performance characteristics necessary to definitively define status in all patients, the majority of diagnostic laboratories rely solely on serum B12. […] There are two main problems with the current test used to ascertain how much B12 the patient has in his or her blood.

• #17 Vitamin B12 Deficiency | AAFP

  https://www.aafp.org/pubs/afp/issues/2003/0301/p979.html

  Vitamin B12 (cobalamin) deficiency is a common cause of macrocytic anemia and has been implicated in a spectrum of neuropsychiatric disorders. […] Diagnosis of vitamin B12 deficiency is typically based on measurement of serum vitamin B12 levels; however, about 50 percent of patients with subclinical disease have normal B12 levels. A more sensitive method of screening for vitamin B12 deficiency is measurement of serum methylmalonic acid and homocysteine levels, which are increased early in vitamin B12 deficiency. […] The diagnosis of vitamin B12 deficiency has traditionally been based on low serum vitamin B12 levels, usually less than 200 pg per mL (150 pmol per L), along with clinical evidence of disease. However, studies indicate that older patients tend to present with neuropsychiatric disease in the absence of hematologic findings.

• #17 Vitamin B12 Deficiency | AAFP

  https://www.aafp.org/pubs/afp/issues/2003/0301/p979.html

  Furthermore, measurements of metabolites such as methylmalonic acid and homocysteine have been shown to be more sensitive in the diagnosis of vitamin B12 deficiency than measurement of serum B12 levels alone. […] In a large study of 406 patients with known vitamin B12 deficiency, 98.4 percent had elevated serum methylmalonic acid levels, and 95.9 percent had elevated serum homocysteine levels (defined as three standard deviations above the mean). […] This finding suggests that methylmalonic acid and homocysteine levels can be early markers for tissue vitamin B12 deficiency, even before hematologic manifestations occur. […] Use of methylmalonic acid and homocysteine levels in the diagnosis of vitamin B12 deficiency has led to some surprising findings. […] This observation suggests that use of a low serum vitamin B12 level as the sole means of diagnosis may miss up to one half of patients with actual tissue B12 deficiency. […] An algorithm for the diagnosis of vitamin B12 deficiency is provided in Figure 3.

• #18 Folate Deficiency Anemia 101: Symptoms, Lab Testing, and Treatment

  https://www.rupahealth.com/post/folate-deficiency-anemia-overview-symptoms-lab-testing-diagnosis-and-treatment

  Elevated homocysteine is suggestive of folate deficiency but is also elevated in vitamin B12 deficiency and kidney disease. […] Methylmalonic acid (MMA) can help differentiate between folate and vitamin B12 deficiency because MMA levels rise in the presence of vitamin B12 deficiency but not in folate deficiency.

• #19 Diagnosing Vitamin B12 Deficiency Anemia | Technology Networks

  https://www.technologynetworks.com/diagnostics/blog/diagnosing-vitamin-b12-deficiency-anemia-335353

  HoloTC, better known as Active-B12, represents 10-30% of the total circulating B12 and is considered the bioactive form of B12. […] The Access Active-B12 assay is a fully automated test available on the Beckman Coulter Access 2, DxI 600 and DxI 800 immunoassay systems. Access Active-B12 is Beckman Coulters newest addition to an already comprehensive menu for anemia disease-state management.

• #19 Diagnosing Vitamin B12 Deficiency Anemia | Technology Networks

  https://www.technologynetworks.com/diagnostics/blog/diagnosing-vitamin-b12-deficiency-anemia-335353

  Though anemia itself is complex, in most cases, it may be diagnosed easily and correctly with the help of a thorough medical history, clinical examination and most importantly, laboratory tests that are specific for diagnosing anemia in all its forms. […] An initial full blood count analysis using a hematology system will detect macrocytic red blood cells, indicating possible vitamin deficiency. Further diagnostic testing for low-serum vitamin B12, as well as any clinical evidence of the deficiency, are traditional paths for the diagnosis of vitamin B12 deficiency. […] With the more recent addition of Active-B12 testing, physicians have access to a more reliable and earlier indicators of B12 deficiency. […] Only holoTC transports vitamin B12 from its site of absorption in the ileum to tissues and cells throughout the body, while holoHC is considered inert or biologically unavailable.

• #20 Pernicious Anaemia and B12 Deficiency | Doctor

  https://patient.info/doctor/pernicious-anaemia-and-b12-deficiency

  The diagnosis of vitamin B12 deficiency should not be excluded solely on the absence of either anaemia or macrocytosis. […] Offer an initial diagnostic test for vitamin B12 deficiency to people who have at least 1 common symptom or sign, and at least 1 common risk factor for the condition. […] Use either total B12 (serum cobalamin) or active B12 (serum holotranscobalamin) as the initial test for unless: Use active B12 as the initial test for suspected vitamin B12 deficiency during pregnancy. […] Identification of hypersegmented neutrophils may suggest either vitamin B12 or folate deficiency; however, they are not sensitive in early vitamin B12 deficiency and are not specific. […] Oval macrocytes, hypersegmented neutrophils and circulating megaloblasts in the blood film and megaloblastic change in the bone marrow are the typical features of clinical vitamin B12 deficiency.

• #20 Pernicious Anaemia and B12 Deficiency | Doctor

  https://patient.info/doctor/pernicious-anaemia-and-b12-deficiency

  Pernicious anaemia is an autoimmune gastritis that causes atrophy of all layers of both the body and fundus of the stomach, and loss of normal gastric glands, mucosal architecture, and parietal and chief cells, leading to atrophic gastritis. This atrophy reduces the number of parietal cells which secrete intrinsic factor (IF). […] IF is essential for the absorption of vitamin B12. Antibodies to IF are very specific for pernicious anaemia, but only present in 50% to 70% of people with the condition. […] The resultant malabsorption of vitamin B12 leads to vitamin B12 deficiency, which ultimately leads to pernicious anaemia. […] Autoimmune gastritis presents with no or vague symptoms, and only becomes a clinical disease when diagnosed in gastric biopsies performed for a variety of clinical indications. Therefore the presentation of pernicious anaemia is much more often that of vitamin B12 deficiency and anaemia, rather than gastrointestinal symptoms.

• #20 Pernicious Anaemia and B12 Deficiency | Doctor

  https://patient.info/doctor/pernicious-anaemia-and-b12-deficiency

  Consider an anti-intrinsic factor antibody test for people with vitamin B12 deficiency if autoimmune gastritis is suspected and they have not previously had a positive anti-intrinsic factor antibody test at any time or an operation that could affect vitamin B12 absorption. […] If vitamin B12 deficiency is diagnosed in pregnancy or during breastfeeding and autoimmune gastritis is the suspected cause, offer an anti-intrinsic factor antibody test if the criteria above is met and start treatment with intramuscular vitamin B12 replacement. […] People with pernicious anaemia are at increased risk of developing gastric cancer and there is an association with other autoimmune diseases, including primary hypothyroidism, thyrotoxicosis, Hashimoto’s thyroiditis, Addison’s disease, type 1 diabetes, hypoparathyroidism and vitiligo.

• #20 Pernicious Anaemia and B12 Deficiency | Doctor

  https://patient.info/doctor/pernicious-anaemia-and-b12-deficiency

  Response to treatment of vitamin B12 deficiency can vary and depends on the cause of the vitamin B12 deficiency. Symptoms may start to improve within 2 weeks, but this may take up to 3 months. […] Lifelong intramuscular vitamin B12 replacement if: autoimmune gastritis is the cause, or suspected cause, of vitamin B12 deficiency, or they have had a total gastrectomy, or a complete terminal ileal resection. […] If vitamin B12 deficiency because of malabsorption that is not caused by autoimmune gastritis, or a total gastrectomy or complete terminal ileal resection: vitamin B12 replacement and consider intramuscular instead of oral vitamin B12 replacement. […] Offer vitamin B12 replacement, and consider oral instead of intramuscular vitamin B12 replacement and review response to treatment at the person’s first follow-up appointment.

• #21 Vitamin B12 Deficiency: Recognition and Management | AAFP

  https://www.aafp.org/pubs/afp/issues/2017/0915/p384.html

  Patients diagnosed with vitamin B12 deficiency whose history and physical examination do not suggest an obvious dietary or malabsorptive etiology should be tested for pernicious anemia with anti-intrinsic factor antibodies (positive predictive value = 95%), particularly if other autoimmune disorders are present.

• #22 Assessment, investigation and diagnosis of B12 deficiency – Primary Care Notebook

  https://primarycarenotebook.com/pages/haematology/vitamin-b12-deficiency/assessment-investigation-and-diagnosis-of-b12-deficiency

  reasonably sensitive but not as specific as anti-IF antibodies […] Urinary methylmalonyl CoA urinary excretion is increased in B12 deficiency – B12 is the co-enzyme in the conversion reaction of methylmalonyl CoA to succinyl CoA […] Clinical picture is the most important factor in assessing the results of the serum vitamin B12. Definitive cut off points for clinical and subclinical deficiency are not possible […] levels are not easily correlated with clinical symptoms, although patients with vitamin B12 levels 100ng/L almost always have clinical or metabolic evidence of vitamin B12 deficiency, and 150ng/l usually do […] in most patients with clinically significant vitamin B12 deficiency, the serum level is below 200ng/L but clinically significant vitamin B12 deficiency may be present even when levels are in the normal range, especially in elderly patients […] about a third of patients with B12 deficiency may not have macrocytosis.

• #23 Addressing the Gaps in the Vitamin B12 Deficiency 2024 NICE Guidelines: Highlighting the Need for Better Recognition, Diagnosis, and Management of Pernicious Anaemia | European Journal of Clinical Nutrition

  https://www.nature.com/articles/s41430-025-01583-4

  While they recommend considering an anti-intrinsic factor autoantibody test if AIG is suspected, the guidelines do not adequately explain why general practitioners should suspect an autoimmune basis beyond typical gastrointestinal symptoms. […] The guidelines acknowledge that a negative IF-Ab test does not rule out AIG or PA, and they suggest additional investigations when clinical suspicion remains. […] Once AIG and/or PA are suspected and/or test results are positive, individuals should undergo a gastroscopy/endoscopy with histological sampling to determine the presence of AIG. […] However, a positive result for IF-ABs can confirm a diagnosis of PA, gastroscopy remains important for confirming AIG and assessing the degree of gastric atrophy. […] The guidelines emphasize a symptom-based approach to treatment is an urgent and necessary shift that could positively influence current practice. […] The guidelines currently lack detailed protocols for diagnosing PA, especially in patients without typical gastrointestinal symptoms, and rely on tests with limited sensitivity and specificity.

• #24 Megaloblastic Anemia | Boston Children’s Hospital

  https://www.childrenshospital.org/conditions/megaloblastic-anemia

  Megaloblastic anemia is diagnosed through a physical exam and other tests, including: […] Blood tests to measure of vitamin B12, methylmalonic acid (MMA), or homocysteine levels […] Blood tests to detect the antibodies toward intrinsic factor or the cells that produce it […] A bone marrow exam may be necessary if the diagnosis is unclear.

• #25 Vitamin B12 deficiency anemia Information | Mount Sinai – New York

  https://www.mountsinai.org/health-library/diseases-conditions/vitamin-b12-deficiency-anemia

  Vitamin B12 deficiency anemia is a low red blood cell count due to a lack (deficiency) of vitamin B12. […] The health care provider will perform a physical exam. This may reveal problems with your reflexes or sensations. […] Tests that may be done include: Complete blood count (CBC), Reticulocyte count, Lactate dehydrogenase (LDH) level, Serum bilirubin level, Serum vitamin B12 level, Serum methylmalonic acid (MMA) level, Serum homocysteine level (amino acid found in blood), Anti-intrinsic factor antibody, Anti-parietal cell antibody. […] Other procedures that may be done include: Esophagogastroduodenoscopy (EGD) to examine the stomach and small intestine, Bone marrow biopsy if the diagnosis is not clear.

• #26 Pernicious anemia – Wikipedia

  https://en.wikipedia.org/wiki/Pernicious_anemia

  Pernicious anemia refers to a type of vitamin B12 deficiency anemia that results from lack of intrinsic factor. […] When suspected, diagnosis is made by blood tests initially a complete blood count, and occasionally, bone marrow tests. […] Diagnosis is not always straightforward and can be challenging. […] Vitamin B12 serum levels are used to detect its deficiency, but do not distinguish its causes. […] The presence of antibodies to gastric parietal cells and intrinsic factor is common in PA. […] These antibody tests can distinguish between PA and food-B12 malabsorption. […] The diagnosis of atrophic gastritis type A should be confirmed by gastroscopy and stepwise biopsy. […] The classic test for PA, the Schilling test, is no longer widely used, as more efficient methods are available.

• #27 ACASM – Overview: Pernicious Anemia Cascade, Serum

  https://www.mayocliniclabs.com/test-catalog/Overview/ACASM

  A group of tests is often required to establish the correct diagnosis as determination of vitamin B12 in serum does not detect all cases of vitamin B12 deficiency. Mayo Clinic’s Department of Laboratory Medicine and Pathology offers a diagnostic algorithm to expedite the identification of patients with vitamin B12 deficiency. This algorithm accounts for the following facts: […] -The most sensitive test for vitamin B12 deficiency at the cellular level is the assay for methylmalonic acid (MMA). […] -Nearly half of the cases of pernicious anemia can be unambiguously identified if the serum test for intrinsic factor blocking antibody is positive (this is simpler and less expensive than MMA). […] -Serum gastrin is usually markedly increased in pernicious anemia (as a result of gastric atrophy), and this test can be used as a substitute for the more complicated and more expensive Schilling test of intestinal absorption of vitamin B12.

• #27 ACASM – Overview: Pernicious Anemia Cascade, Serum

  https://www.mayocliniclabs.com/test-catalog/Overview/ACASM

  The algorithm is similar to that published by Green, except that the serum gastrin assay is performed in place of the Schilling test. Experience with both Mayo Clinic and Mayo Clinic Laboratories’ cases has corroborated that this is a cost-effective alternative to the Schilling test. […] In our experience, greater than 90% of laboratory test costs can be saved by using the algorithm rather than ordering all the services for a patient suspected of having B12 deficiency. Furthermore, the substitution of the serum gastrin assay for the Schilling test offers 3 advantages: […] 1. It is an in vitro test that does not require administration of radioisotopes to patients […] 2. It can be performed on mailed-in specimens […] 3. It is much less expensive […] Only those tests that are appropriate, as defined by the algorithm, will be performed.

• #27 ACASM – Overview: Pernicious Anemia Cascade, Serum

  https://www.mayocliniclabs.com/test-catalog/Overview/ACASM

  For more information see Vitamin B12 Deficiency Evaluation. […] If the vitamin B12 concentration is less than 150 ng/L, then the intrinsic factor blocking antibody (IFBA) test is performed at an additional charge. […] If IFBA result is negative or indeterminate, then the gastrin test is performed at an additional charge. […] If the vitamin B12 concentration is 150 to 400 ng/L, then the methylmalonic acid (MMA) test is performed at an additional charge. […] If the MMA result is greater than 0.40 nmol/mL, then the IFBA test is performed at an additional charge. […] If the IFBA test is negative or indeterminate, then the gastrin test is performed at an additional charge.

• #28 Pernicious anaemia: recognition, diagnosis and management – The Pharmaceutical Journal

  https://pharmaceutical-journal.com/article/ld/pernicious-anaemia-recognition-diagnosis-and-management

  Owing to the insidious onset of symptoms and limitations in diagnostic testing, many patients experience delays in diagnosis, with studies indicating that 38% of patients wait five years or more before diagnosis. […] Diagnosis and management of pernicious anaemia is currently imprecise, with many unanswered questions and a lack of consistency in practise.

• #29 Vitamin B12 Deficiency in Dialysis Patients: Risk Factors, Diagnosis, Complications, and Treatment – A Comprehensive Review

  https://clinmedjournals.org/articles/jcnrc/journal-of-clinical-nephrology-and-renal-care-jcnrc-10-098.php?jid=jcnrc

  Vitamin B12 deficiency presents a diagnostic dilemma in dialysis patients. Vitamin B12, homocysteine, and methylmalonic acid levels have not been examined in this population as markers of B12 insufficiency and have not been validated as gold standard diagnostic tools. Measuring serum vitamin B12 levels is often used as a first-line screening test, but the sensitivity and specificity vary widely across studies. Serum B12 levels less than 100 pg/mL have been shown to have a specificity of 90% for identifying clinically evident deficiency. However, it has been demonstrated that low vitamin B12 concentrations do not necessarily imply deficiency, and levels in the lower half of the reference interval do not rule out deficiency. Moreover, vitamin B12 levels can be falsely normal or high in dialysis patients due to the presence of inactive analogues of vitamin B12 in the blood.

• #30 Anaemia, vitamin B12 or folate deficiency – Diagnosing vitamin B12 or folat

  https://www.ibdrelief.com/learn/complications-of-ibd/vitamin-and-mineral-deficiencies-in-ibd/vitamin-b12-and-ibd/anaemia-vitamin-b12-or-folate-deficiency-diagnosing-vitamin-b12-or-folate-deficiency-anaemia

  A diagnosis of vitamin B12 or folate deficiency anaemia can often be made by your GP based on your symptoms and the results of blood tests. […] Different types of blood tests can be carried out to check: whether you have a lower level of haemoglobin (a substance that transports oxygen) than normal, whether your red blood cells are larger than normal, the level of vitamin B12 in your blood, the level of folate in your blood. […] These tests can often help identify people with a possible vitamin B12 or folate deficiency, but they are not necessarily conclusive, because some people can have problems with normal levels of these vitamins, and others can have low levels despite having no symptoms. […] This means it is very difficult to devise definitive criteria for the diagnosis of vitamin B12 or folate deficiency, and this is why it is important for your symptoms to be taken into account when a diagnosis is made.

• #31 Diagnosis, Treatment and Long-Term Management of Vitamin B12 Deficiency in Adults: A Delphi Expert Consensus

  https://www.mdpi.com/2077-0383/13/8/2176

  Background/Objectives: Vitamin B12 deficiency can cause variable symptoms, which may be irreversible if not diagnosed and treated in a timely manner. […] Recognition of clinical symptoms should receive the highest priority in establishing the diagnosis. There is agreement that the serum B12 concentration is useful as a screening marker and methylmalonic acid or homocysteine can support the diagnosis. […] The severity of vitamin B12 deficiency symptoms at first presentation affects the choice of treatment modality. […] The algorithm for diagnosing vitamin B12 deficiency and its causes was agreed upon among the panelists. […] The panelists agreed that the delay in the diagnosis of vitamin B12 deficiency may be explained by barriers such as the variability of symptoms, low doctor awareness of the disease, not paying attention to the patient’s symptoms, and limited access to modern laboratory markers.

• #31 Diagnosis, Treatment and Long-Term Management of Vitamin B12 Deficiency in Adults: A Delphi Expert Consensus

  https://www.mdpi.com/2077-0383/13/8/2176

  The panelists agreed that symptoms related to the peripheral and central nervous systems are the most common symptoms in patients with clinically manifested vitamin B12 deficiency. […] The detection and treatment of vitamin B12 deficiency during pregnancy, lactation, and infancy should receive high priority due to the otherwise serious impact on fetal and infant development. […] The decision on the route of B12 administration should consider patients’ preference that may change during long-term treatment.

• #32 3.7 Vitamin B12 and Folate Deficiency Anemia – Health Alterations

  https://wtcs.pressbooks.pub/healthalts/chapter/3-7-vitamin-b12-and-folate-deficiency-anemia/

  Medical Interventions for vitamin B12 deficiency depend on the cause, as well as the severity of the disorder. Common medical treatments include Vitamin B12 Supplements (Cyanocobalamin), Routine Monitoring of Vitamin B12 Levels, and Blood Transfusions. […] During the evaluation stage, nurses determine the effectiveness of nursing interventions for a specific client. Lab results showing improvement of anemia resulting from vitamin B12 or folate deficiency should improve within one to two weeks and normalize within one to two months.

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