Establishment of internal quality control system in anti-mitochondrial antibody subtype M2 detection by using human serum as quality control material

Internal quality control (QC) material is important for day-to-day checking of analytical processes in a clinical laboratory. For anti-mitochondrial antibody subtype M2 (AMA-M2) detection, there are no commercial QC materials available. In this study, pooled serum was evaluated as internal QC material for AMA-M2 detection. Remnant serum samples of primary biliary cirrhosis (PBC) patients requested for AMA-M2 were collected after test. The collected samples were pooled and homogenized. After heat-inactivation the pooled serum was divided in aliquots as internal QC material. The stability of the internal QC material and the precision of the AMA-M2 detecting system were evaluated, and a 20-day daily internal QC test was assessed. The quality of pooled serum was reliable, and the validity period could last for more than 16 months. The precision of AMA-M2 signal intensity detection was stable with a mean value 112.7 and coefficients of variation (CV) 9.7% in repetitive tests of one same sample, and a mean value 113.4 and CV 11.8% in different sample. Considering the 20-day daily internal QC evaluation period, the CV of the internal QC results was 8.1% which achieved the goal of internal quality control. The results suggest that the home-made AMA-M2 internal QC material was stable and reliable. The AMA-M2 signal intensity detection system has high precision. The home-made AMA-M2 internal quality control system has a good application value for its stability, precision, and cost effectiveness.