Test results from a single drop of blood are highly variable, according to a study published in the American Journal of Clinical Pathology. This variation between successive drops of fingerprick blood may be even greater than variation between fingerprick and venous blood samples. As a result, the authors say, tests may need to be run on six to nine drops of blood, rather than one. This study’s findings may affect many aspects of clinical testing. It could pose a problem for clinical decisions based on fingerprick tests, like anemia testing, and it could impact the future development of point-of-care diagnostics. Finally, this variability may also add momentum to the swirling of questions disputing the capabilities of Theranos’ micro-sample technology. “These data suggest caution when using measurements from a single drop of fingerprick blood,” writes co-author Rebecca R. Richards-Kortum, Ph.D., from Rice University in Houston. “Our results show that people need to take care to administer fingerprick tests in a way that produces accurate results because accuracy in these tests is increasingly important for diagnosing conditions like anemia, infections and sickle-cell anemia, malaria, HIV and other diseases.” Fingerpricks are often used in point-of-care testing and are preferred over venipuncture because of […]