Difference in bias approach for commutability assessment: application to frozen pools of human serum measured by 8 direct methods for HDL and LDL cholesterol.

BACKGROUND: We used a difference in bias approach to evaluate the commutability of 4 frozen serum pools for 8 direct methods for measurement of HDL and LDL cholesterol (HDLC and LDLC). METHODS: Freshly collected nonfrozen sera from 138 diseased and 37 nondiseased patients and 4 frozen pools from the CDC Lipid Standardization Program were measured by direct methods and by the beta-quantification reference measurement procedure of the CDC. We used an error components model to estimate the difference in the bias component of error plus its uncertainty for frozen pools vs patient samples between the direct method and the reference procedure. Frozen pools with bias differences less than a critical value determined by either medical requirements for bias or the random error components of the measurement procedures were considered commutable. RESULTS: On the basis of medical requirement criteria, 1 of the 4 frozen pools was commutable for most of the HDLC methods for both diseased and nondiseased patients, and none was commutable for LDLC methods. On the basis of random error criteria, all of the frozen pools were generally commutable for all of the HDLC methods for both diseased and nondiseased patients, and 1 of the 4 frozen pools was generally commutable for most of the LDLC methods for both diseased and nondiseased patients. CONCLUSIONS: Commutability was assessed as the closeness of agreement of the difference in bias between a reference material and a set of patient samples. Criteria for commutability could be based on fixed medical requirements for bias or on random error components.

[Current status for OTC examination (test)].

Upgrading and expanding of preventive measures for lifestyle-related diseases is an urgent national priority because they are recognized as the most important health risks by both the general population and government. With such a social background, the spread of self-medication by self-test is eagerly awaited by health-oriented individuals. In this paper, legal position of OTC test reagent, OTC test equipment and remote healthcare as current status of OTC test are explained, reference is made to the current status of their diffusion here in Japan, and some typical examples of "self-collection sample and corresponding OTC test item" are clearly described. In consideration of the large number of potential patients with folk disease such as metabolic syndrome, drug stores should be an accessible and convenient spot for Japanese people to enjoy the benefit of OTC test by obtaining test kits for such diseases.