title: Sensitivity and specificity of mean corpuscular volume testing for screening for alpha-thalassemia-1 and beta-thalassemia traits.
abstract: OBJECTIVE
  To evaluate the sensitivity, specificity, positive predictive value and negative predictive value of mean corpuscular volume (MCV) testing for screening for both alpha-thalassemia-1 and beta-thalassemia traits.
  
  
  METHODS
  A diagnostic test was conducted on 439 pregnant women attending the antenatal care (ANC) clinic at Maharaj Nakorn Chiang Mai Hospital between April 2002 and July 2002. Blood samples were collected from the pregnant women after they were counseled and gave informed consent. The MCV was measured in all samples using an automated hematology analyzer. The hemoglobin (HbA2) level and polymerase chain reaction (PCR) were measured in all cases to test for the beta-thalassemia trait and the alpha-thalassemia-1 gene (South-East Asian [SEA] type), respectively. The data were collected and analyzed for sensitivity, specificity, positive predictive value and negative predictive value for evaluating the efficacy of MCV testing for screening for both alpha-thalassemia-1 and beta-thalassemia traits.
  
  
  RESULTS
  Positive MCV tests (</=80 fl) showed a sensitivity of 92.9% and specificity of 83.9% in screening for alpha-thalassemia-1 and beta-thalassemia traits, respectively. The positive predictive value and negative predictive value were 37.9% and 99.1%, respectively.
  
  
  CONCLUSIONS
  MCV evaluation is a useful tool for screening for alpha-thalassemia-1 and beta-thalassemia traits during pregnancy because of its simplicity, low cost and high sensitivity.
authors.affiliation: Department of Obstetrics and Gynecology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand. ssiricho@mail.med.cmu.ac.th
authors.forename: Supatra
authors.initials: S
authors.lastname: Sirichotiyakul
authors.forename: Jatuchai
authors.initials: J
authors.lastname: Maneerat
authors.forename: Torpong
authors.initials: T
authors.lastname: Sa-nguansermsri
authors.forename: Pisawat
authors.initials: P
authors.lastname: Dhananjayanonda
authors.forename: Theera
authors.initials: T
authors.lastname: Tongsong
mesh_terms: D000328:Adult; D004909:Erythrocyte Indices; D005260:Female; D006801:Humans; D011237:Predictive Value of Tests; D011247:Pregnancy; D011250:Pregnancy Complications, Hematologic / Q000097:blood / Q000175:diagnosis*; D011296:Prenatal Diagnosis; D012680:Sensitivity and Specificity; D017085:alpha-Thalassemia / Q000097:blood / Q000175:diagnosis*; D017086:beta-Thalassemia / Q000097:blood / Q000175:diagnosis*