2018 Volume 67 Issue 2 Pages 196-203
We investigated the appropriateness of samples for external accuracy control using a prostate-specific antigen (PSA), ferritin, α-fetoprotein (AFP), and carcinoembryonic antigen (CEA) as test items and found the usefulness of pooled serum in the first report. In this study, we evaluated devices and reagents from 13 manufacturers. Two series of PSA, ferritin, and AFP and four series of CEA of 5-fold serial dilutions of serum were prepared with sera from different patients. The CV of measured values of PSA was 8.6–11.9%, and none of the values showed deviation. The CV of measured values of ferritin was 13.5–19.5%, and differences among the origins of the samples were noted in two devices. In AFP, the value of one sample deviated in one device, and CV was 10.6%, but the CVs of the other samples were 4.5–7.2%. CEA was measured in serum samples prepared from patients with cancers of different organs. The mean CV of samples from colorectal cancer patients was 10.9%, and that of samples from breast cancer patients was 19.9%, showing a difference in reactivity between the origins of samples.
