Reliability of the medical laboratory test in the Korean National Health and Nutritional Examination Survey (KNHANES) is very important for the evaluation of prevalence of chronic disease such as hyperlipidemia, chronic kidney disease or diabetes. The...
Reliability of the medical laboratory test in the Korean National Health and Nutritional Examination Survey (KNHANES) is very important for the evaluation of prevalence of chronic disease such as hyperlipidemia, chronic kidney disease or diabetes. Therefore, strict quality control of the examination is required. Since 2008, this project has made an effort to improve the reliability of the examination results by evaluating the Neodin Medical Institute, which performs diagnostic medical examinations for KNHANES, through laboratory inspections, evaluation of internal and external quality controls, inter-laboratory comparisons, and traceability and reproducibility tests. In the 2013 KNHANES, tests for ferritin, iron (Fe), and insulin were excluded and those for thyroid stimulating hormone (TSH), free thyroxine (T4), anti-thyroid peroxidase antibody (anti-TPO antibody) and iodine (U) were added to the test items. Results of the evaluation of laboratory inspection, internal and external quality control were generally satisfactory. Inter-laboratory comparison, which were performed in assay including TSH, Free T4, anti-TPO Ab, Iodine (U), and anti-hepatits C virus (HCV) antibody showed that correlation was high for all items. Most differences in results were within acceptable ranges for variability, indicating that they were equivalent. The reproducibility tests had very good correlation and coefficients of variation (CVs) were considered quite good. Progress trends comparison between 2010 and 2013 showed that most items showed consistent results; however, positive bias was observed for results of the high density lipoprotein (HDL)-cholesterol test when compared with the results of tests conducted in 2012. Hence, trends of HDL cholesterol test results should be closely monitored. Traceability tests using reference institutes for creatinine, total cholesterol, HDL, LDL, and TG showed that HDL and creatinine results compared with those of reference institutes exceeded acceptable range, therefore, close observation will be necessary. Traceability tests using standard reference material for glucose, lead, mercury, cadmium, Vit D, and urine creatinine showed that the measurements were within the acceptable range. In summary, quality control has been improving for KNHANES to date. Positive bias observed for the results of HDL and creatinine traceability tests can be avoided by quality control as well as long-term efforts of the domestic reference laboratories to obtain international certification along with cooperation from the reagent companies. Continuous management, through evaluations such as laboratory inspections and by maintaining accuracy and traceability of the examinations by using reference institutes or reference material measurements, will be necessary.