Report of the Korean Association of External Quality Assessment Service on Complement and Immunoglobulin (2018)

Kyeong-Hee Kim Department of Laboratory Medicine, Dong-A University College of Medicine, Busan, Korea In 2018, the complement and immunoglobulin proficiency testing program of the Korean Association of External Quality Assessment Service included complement, free light chain, immunoglobulin, and anti-cyclic citrullinated peptide (anti-CCP). Tests on all nine items were conducted. The specimen used in the complement and immunoglobulin proficiency testing program was Liquichek Immunology Control from Bio-Rad (Bio-Rad Laboratories, USA). In April and October, three quality control specimens were frozen and delivered. The quantitative proficiency testing report included the number of participating organizations in each group, mean, standard deviation, coefficient of variation (CV), median, minimum, and maximum values. The number of organizations participating in each test varied and ranged from 29 free light chains to 115 anti-CCP participants. The median CV of C3 was 4.9%, and the median CV of C4 was 8.45%, which was statistically significantly lower (P=0.013). The median CV for the free light chain κ and the free light chain λ were 7.96 and 6.21, respectively, with a high CV for the free light chain κ, but no statistical difference (P=0.092). The median CV of immunoglobulin A (IgA), immunoglobulin G (IgG), and immunoglobulin M (IgM) were good at 4.5, 4.48, and 3.56, but the median CV of immunoglobulin E was 7.75, which was statistically significantly higher than that of IgA, IgG, and IgM (P=0.0014). The anti-CCP, which evaluated the qualitative results, was correct 99.1–100% of the time, with the exception being for the IG-18-02 specimen. The anti-CCP, which lacks international standards, requires patient-derived proficiency testing materials. (Lab Med Qual Assur 2019;41:195-200)