ABSTRACT
A new test [Dr. KSU H1N1 RT-PCR kit] was recently developed to provide a less expensive alternative to reAl time reverse transcriptase-polymerase chain reaction [RT-PCR]. We report the findings of a validation study designed to assess the diagnostic accuracy, including sensitivity and specificity, of the new kit, as compared to reAl time RT-PCR. Cross-sectional validation study conducted from 18-22 November 2009 at a primary care clinic for H1N1 at a tertiary care teaching hospital in Riyadh. Nasopharyngeal swab samples and data on socio-demographic characteristics and symptoms were collected from 186 patients. Swab samples were sent to the laboratory for testing with both reAl time RT-PCR and the new Dr. KSU H1N1 RT-PCR kit. We measured the sensitivity and specificity of the new test across the entire sample size and investigated how these values were affected by patient socio-demographic characteristics and symptoms. The outcomes of the two tests were highly correlated [kappa=0.85; P<.0001]. The sensitivity and specificity of the new test were 99.11% and 83.78%, respectively. The sensitivity of the new test was affected only minimally [96%-100%] by patient characteristics and number of symptoms. On the other hand, the specificity of the new test varied depending on how soon patients were tested after onset of symptoms [100% specificity when swabs were taken on the first day of the symptoms, decreasing to 75% when swabs were taken on or after the third day]. The specificity of the new test also increased with increasing body temperature. The new test seems to provide a cost-effective alternative to reAl time RT-PCR for diagnosing H1N1 influenza. However, further testing may be needed to verify the efficacy of the test in different settings and communities