Validation, performance, and reliability of two automated tests for vitamin B12 and folate assay

Deficiency of Vitamin B12 and folate may determine hematological, neurological, and metabolic alterations; therefore, an accurate quantification of their serum levels is required, especially in the presence of symptoms that might suggest a deficiency. CHORUS VIT B12 and CHORUS FOLATE are two automated immunoassays, developed to quantify vitamin B12 and folate, respectively, in human serum.

This single-center, non-pharmacological, diagnostic study described the validation and characterization of CHORUS VIT B12 and CHORUS FOLATE, with a specific focus on performance, precision, and reliability. For each assay, 500 serum samples were analyzed. A comparison between CHORUS assays and commercially available kit was also performed.

For CHORUS VIT B12 the lower limit of quantification (LLoQ) was 165.0 pg/mL and the upper LoQ (ULoQ) was 1846.8 pg/mL. The assay was linear within the calibration range (150-2000 pg/mL) and the accuracy was described with the International Standard Vitamin B12, Serum Folate, HOLO TC (NIBSC code: 03/178), with a mean recovery on two lots of 111%. For CHORUS FOLATE (calibration range of 2.0-20.0 ng/mL), LLoQ was 2.0 ng/mL and ULoQ 19.6 ng/mL. The linearity was demonstrated from 2.4 to 20.0 ng/mL; the accuracy was described with the International Standard mentioned above, achieving a mean recovery on three lots of 92%. The lowest and highest values of both CHORUS and COBAS kits were similar and the median values did not significantly vary.

CHORUS VIT B12 and CHORUS FOLATE performed well, accurately, and reliably in quantifying vitamin B12 and folate in human serum.