Evaluation of the Keystone Diagnostic Quik Test. A paper chromatography test for drugs of abuse in urine.

The Keystone Diagnostic Inc (KDI) Quik Test is advertised to be an on-site, rapid, broad-spectrum paper chromatography test that is marketed for use in industry, drug abuse treatment facilities, and physician's offices. Even when unskilled individuals perform the test, five drugs of abuse, excluding marijuana, are said by the manufacturer to be reliably detected. In this study, ten confirmed drug-free urine specimens and 56 specimens positive by an immunoassay screening test, and confirmed by gas chromatography/mass spectrometry, for cocaine (n = 32), phencyclidine (n = 12), or opiate drugs (n = 12), were reanalyzed by the KDI Quik Test. The sensitivity of the KDI Quik Test was 62.5%, specificity was 70%, predictive value of a negative test was 36%, and efficiency was 64%. In too many instances the KDI Quik Test did not detect the drugs for which it is intended. Paper chromatography tests such as the KDI Quik Test are inaccurate and as such are unacceptable in any setting for the purposes of screening for drugs of abuse.