title: A validation study comparing the sensitivity and specificity of the new Dr. KSU H1N1 RT-PCR kit with real-time RT-PCR for diagnosing influenza A (H1N1).
abstract: OBJECTIVE
  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.
  
  
  METHODS
  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.
  
  
  METHODS
  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.
  
  
  RESULTS
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Family and Community Medicine, King Saud University, Riyadh, Saudi Arabia. abinsaid@ksu.edu.sa
authors.forename: Abdulaziz A
authors.initials: AA
authors.lastname: Binsaeed
authors.forename: Abdulaziz A
authors.initials: AA
authors.lastname: Al-Khedhairy
authors.forename: Ahmed M A
authors.initials: AM
authors.lastname: Mandil
authors.forename: Shaffi A
authors.initials: SA
authors.lastname: Shaikh
authors.forename: Riaz
authors.initials: R
authors.lastname: Qureshi
authors.forename: Abdulaziz S
authors.initials: AS
authors.lastname: Al-Khattaf
authors.forename: Hanan A
authors.initials: HA
authors.lastname: Habib
authors.forename: Awatif A
authors.initials: AA
authors.lastname: Alam
authors.forename: Lubna A
authors.initials: LA
authors.lastname: Al-Ansary
authors.forename: Mohammed
authors.initials: M
authors.lastname: Al-Omran
mesh_terms: D000293:Adolescent; D000328:Adult; D001831:Body Temperature; D002648:Child; D002675:Child, Preschool; D003362:Cost-Benefit Analysis; D003430:Cross-Sectional Studies; D005260:Female; D006784:Hospitals, Teaching; D006801:Humans; D007223:Infant; D053118:Influenza A Virus, H1N1 Subtype / Q000302:isolation & purification*; D007251:Influenza, Human / Q000175:diagnosis* / Q000821:virology; D008297:Male; D008875:Middle Aged; D011320:Primary Health Care; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000191:economics / Q000379:methods*; D012529:Saudi Arabia; D012680:Sensitivity and Specificity; D013997:Time Factors; D055815:Young Adult