Diagnosing Vitamin B12 Deficiency Anemia

Anemia is the most common blood disorder, estimated to affect around 25% of the world’s population. It occurs when a person lacks enough red blood cells, or the cells do not function as they should, resulting in insufficient levels of oxygen transported around the body. There are several different types of anemia, with a variety of causes, including blood loss, vitamin deficiencies such as B12, immune disorders, and congenital abnormalities. Diagnosing anemia and identifying the cause is an important step in selecting appropriate therapeutic measures.

Beckman Coulter has recently expanded their range of tools for anemia diagnosis, with the launch of the Access Active-B12 Assay. We spoke to Heather Read-Harper, European Senior Manager for Immunoassay and Clinical Chemistry at Beckman Coulter, to learn more about the assay and the advantages of detecting Active-B12.

Anna MacDonald (AM): Why can accurate diagnosis of anemia be difficult?

Heather Read-Harper (HR): Anemia is a globally prevalent and persistent problem. By nature, it is very complex due to the fact that there are multiple types of anemia, many of which often coexist and result from a number of causes. Proper diagnosis requires information from a wide variety of laboratory tests combining various specialties such as hematology, clinical chemistry and immunodiagnostics. Initially, routine hematology analysis such as hemoglobin concentration, red cell count and red cell indices will provide the first indications to guide the diagnosis toward a specific type of anemia. For a more in-depth investigation, additional clinical chemistry and immunodiagnostic laboratory tests are used by physicians in the final diagnosis of a specific type of anemia. Such tests might include serum iron, transferrin, iron-binding capacity, ferritin, soluble transferrin, folate, Active B12 and intrinsic factor Ab.

AM: Why is it so important to identify the exact cause of anemia?

HR: 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. Once the cause has been identified, appropriate treatment, monitored by laboratory testing, can be initiated to resolve the anemia and help people live healthier and fuller lives.

AM: Can you tell us a little about vitamin B12 deficiency and its significance?

HR: Vitamin B12 (cobalamin) is an essential nutrient naturally found in meat, fish, and dairy products and can only be obtained through dietary intake. B12 deficiency can be prevalent in individuals who consume no animal-sourced foods or vegetarians who eat too little egg or dairy products. The condition is also prevalent in the elderly where conditions such as atrophic gastritis, pernicious anemia, Crohn’s disease or immune system disorders can impact how the body absorbs vitamin B12. Prevention of low and deficient vitamin B12 status is of public health importance because it is associated not only with classical deficiency symptoms—such as haematologic abnormalities and irreversible neurological complications—but also potentially with a number of common age-related problems such as cognitive decline, cardiovascular disease, and bone fractures. 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.

AM: What is holoTC and why is it advantageous to detect this molecule?

HR: Vitamin B12 in circulation exists in two forms: holotranscobalamin (holoTC) and holohaptocorrin (holoHC). 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. HoloTC, better known as Active-B12, represents 10–30% of the total circulating B12 and is considered the bioactive form of B12. While traditional serum B12 testing measures the entirety of circulating B12 only the Active-B12 assay measures the critical form.

AM: Can you tell us more about the Access Active-B12 assay?

HR: 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 Coulter’s newest addition to an already comprehensive menu for anemia disease-state management. With the largest measuring range on the market, fastest time to first result and standardisation to WHO International Standard (IS) 03/178, the Access Active-B12 delivers confidence and flexibility over other methods for B12 testing.

Heather Read-Harper was speaking to Anna MacDonald, Science Writer, Technology Networks.