Advice

Summary

Summary

The Abbott ARCHITECT Active‑B12 assay is a test for detecting levels of serum holotranscobalamin, which is the metabolically available component of vitamin B12, and can be used as a marker of vitamin B12 deficiency. Four diagnostic test accuracy studies, using different reference standards, reported greater diagnostic accuracy for the Active‑B12 assay compared with assays measuring other markers of vitamin B12 deficiency. The assay needs less sample preparation than a total vitamin B12 test and the expected cost is about £3.50 per test including VAT, depending on sample throughput.

Product summary and likely place in therapy

  • The Active‑B12 assay detects levels of serum holotranscobalamin (holoTC). HoloTC is the metabolically available component of vitamin B12 (cobalamin), and can be used as a marker of vitamin B12 deficiency.

  • The Active‑B12 assay would be used in place of current tests in people with suspected vitamin B12 deficiency.

Accuracy and effectiveness

  • Eight studies investigated the diagnostic performance of the Active‑B12 assay against other blood markers of vitamin B12.

  • Four of the 8 studies that assessed the diagnostic accuracy of the Active‑B12 assay against different reference standards reported better accuracy than assays for either cobalamin, folate, homocysteine (Hcy) or methylmalonic acid (MMA).

  • One study found low concordance between Active‑B12 holoTC results and MMA levels in samples (n=106) with low or borderline vitamin B12 levels. Active‑B12 test results were in the normal range in 13 samples with low total vitamin B12 and raised MMA or Hcy levels, showing the potential for the Active‑B12 assay to give false negative results.

  • One study found that MMA was elevated in 31% of samples with an indeterminate holoTC result.

  • Two studies assessed concordance between holoTC and total vitamin B12 levels in different clinical groups and concluded that holoTC was a more sensitive marker of deficiency than total vitamin B12.

  • The evidence suggests that testing for holoTC using the Active‑B12 assay may improve diagnostic accuracy when assessing for vitamin B12 deficiency.

Technical and patient factors

  • The Active‑B12 assay is used in hospital laboratories to test blood samples from patients who are suspected of having vitamin B12 deficiency and who present in community or hospital settings.

  • The target population includes people with suspected pernicious anaemia, with known gastrointestinal and pancreatic disorders associated with vitamin B12 deficiency, or presenting with clinical symptoms of vitamin B12 deficiency.

  • The Abbott ARCHITECT Active‑B12 assay can be run on the Abbott ARCHITECT i2000SR or i1000SR analysis systems. The assay needs less sample preparation than a total vitamin B12 test.

Cost and resource use

  • The manufacturer of the Abbott ARCHITECT Active‑B12 assay states that an expected cost per test would be around £3.50 including VAT, depending on sample throughput. Running the Active‑B12 test needs an Abbott ARCHITECT i2000SR or i1000SR analysis system, the cost of which depends on if it is bought or rented, on reagent purchases and contract length.

  • One of the comparator tests, the Biohit Active‑B12, would cost £14.45 per test (excluding VAT).