Abstract:
Abstract
Aim: This study was undertaken to compare the diagnostic sensitivity and specificity of
total vitamin B 12 analyses to active B 12 (holoTC) analyses in a population of patients
attending the Dr George Mukhari Hospital in Pretoria.
Methods: Routine serum folate, full blood count (FBC), thyroid function test,
homocysteine, serum total vitamin B 12 and active B 12 analyses were performed on 30
samples.
Results: Serum folate was determined in all patients and 96% of the patients had a
normal folate value. When looking at the FBC results it is important to note that three
times as many males as females presented with anemia (36% versus 16%). Thyroid
function tests were normal in 90% of patients. When the total vitamin B 12 test was
preformed only 10% of patients tested positive for vitamin B 12 deficiency, in contrast to
the active B12 analyses where 16% of patients tested positive for vitamin B12 deficiency.
Both tests had a diagnostic sensitivity of 50%. The diagnostic specificity for total vitamin
B12 was 93% in comparison with the 86% obtained by the active B12 analyses; when
homocysteine was used as the true marker for vitamin B12 deficiency.
Conclusion: Diagnostic sensitivity was the same and the total vitamin B12 test's
specificity was better in comparison to the active B 12 analyses. Thus the active B 12
assay cannot be recommended for routine use, since it has no benefit.
