Proficiency testing matters.

Far too many laboratories consider proficiency testing just a necessary evil, little more than periodic pass–fail exercises we perform solely to meet regulatory requirements. In addition, too many of us belittle point-of-care (POC)2 testing as a passing fad, a technology so inferior to what we use in our own laboratories that it hardly warrants our attention. Clearly, a report that combines these 2 topics, such as the one in this issue of Clinical Chemistry (1), runs the risk of commanding little attention. That would be a very unfortunate mistake, because it has important lessons for all of us who practice laboratory medicine in our efforts to improve patient care. As Stavelin et al. (1) suggest, POC testing represents an important and growing segment of laboratory medicine. Many important clinical decisions are based on these technologies. Even if the CVs of POC testing, and indeed their accuracies, are not as good as central-laboratory techniques, POC testing modalities can sometimes have a more positive impact on certain aspects of healthcare. A POC creatinine test that predicts a patient's risk for contrast-induced nephropathy and is carried out in 10 min in the emergency room prior to radiologic imaging trumps (as long as it is “good enough”) a central-laboratory test that takes 30 min (or longer) to reach the caregivers (2). Even in nonurgent situations, the availability of such POC tests can be extremely valuable in preventing contrast-induced nephropathy (3). Among the more common, and more important, decisions that clinicians make on the basis of laboratory test results are those related to achieving therapeutic international normalized ratios (INRs) in the management of oral anticoagulants (specifically, vitamin K antagonists such as warfarin). In general, data indicate that POC devices can perform reasonably well analytically (4, 5). In addition, the use of POC …