Nonisotopic binding assay for measuring vitamin B12 and folate in serum.
We evaluated a nonisotopic method (CEDIA; cloned enzyme donor immunoassay) for estimating vitamin B12 and folate in serum. The assays were performed with a Cobas-Mira analyzer. Intra-assay CVs were from 3.7% to 11.0% for vitamin B12 and from 1.2% to 10.7% for folate. Interassay CVs ranged from 9.5% to 11.9% for vitamin B12 and from 6.1% to 18.5% for folate. Linearity was satisfactory, with analytical recovery of 94% at 8.7 and 25.4 nmol/L for folate and 280 and 554 pmol/L for vitamin B12. The detection limit was 3.6 nmol/L for folate and 12.3 pmol/L for vitamin B12. Results of this assay correlated well with those of a conventional radioassay: r = 0.98 for vitamin B12 (n = 51) and r = 0.97 for folate (n = 57). The CEDIA was easy to perform but appeared to be unreliable for use with samples from myeloma patients.
van der Weide
J
J
Department of Clinical Chemistry and Hematology, Hospital De Lichtenberg, Amersfoort, The Netherlands.
Homan
H C
HC
Cozijnsen-van Rheenen
E
E
Vivié-Kipp
Y
Y
Poortman
J
J
Kraaijenhagen
R J
RJ
D005492:Folic Acid / Q000097:blood*; D006801:Humans; D007118:Immunoassay / Q000379:methods* / Q000592:standards / Q000706:statistics & numerical data; D010266:Paraproteins; D011786:Quality Control; D014805:Vitamin B 12 / Q000097:blood*
D010266:Paraproteins; D005492:Folic Acid; D014805:Vitamin B 12