title: Screening for beta-thalassaemia trait in anaemic pregnant women.
abstract: OBJECTIVE
  To find a clinically practicable parameter for the identification of beta-thalassaemia trait (beta-TT) in anaemic pregnant women on the basis of routine use of haematological examination.
  
  
  METHODS
  During 1998-2002, 304 anaemic pregnant women were observed in anaemia consultation hours. A retrospective study was carried out with the aim of finding a screening method for beta-TT in anaemic pregnant women. We compared a sensitivity and a specificity of six different parameters for identification of beta-TT. On the basis of a sensitivity and a specificity for each parameter, we calculated Youden's index, the likelihood ratio and determined the receiver-operating curves. The logistic regression of the variables MCV, MCH and microcytosis was accomplished.
  
  
  RESULTS
  The analysis using receiver-operating curves as well as a calculation of Youden's index showed that the best parameter for screening of beta-TT in anaemic pregnant women is MCV < or = 75 fl. For differentiation between patients with iron deficiency anaemia (IDA) alone and patients with beta-TT and concomitant IDA, microcytosis > or = 15% was the most sensitive. By using MCH we identified 100% of patients in the group with beta-TT but only 67% of patients in the group with IDA.
  
  
  CONCLUSIONS
  Our results suggest identification of beta-thalassaemia on the basis of quantification of HbA2 in all patients with MCV < or = 75 fl and normal iron status.
authors.affiliation: Department of Obstetrics and Gynecology, Institute of Obstetric Research, Fetomaternal Hematology Unit, Zurich University Hospital, Zurich, Switzerland. gabriela.bencaiova@usz.ch
authors.forename: Gabriela
authors.initials: G
authors.lastname: Bencaiova
authors.forename: Tilo
authors.initials: T
authors.lastname: Burkhardt
authors.forename: Alexander
authors.initials: A
authors.lastname: Krafft
authors.forename: Roland
authors.initials: R
authors.lastname: Zimmermann
mesh_terms: D018798:Anemia, Iron-Deficiency / Q000097:blood / Q000175:diagnosis*; D004906:Erythrocyte Count; D004909:Erythrocyte Indices; D005260:Female; D006443:Hemoglobin A2 / Q000032:analysis*; D006453:Hemoglobinopathies / Q000097:blood / Q000517:prevention & control*; D006801:Humans; D016013:Likelihood Functions; D008403:Mass Screening / Q000379:methods*; D011247:Pregnancy; D012372:ROC Curve; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D013557:Switzerland / Q000453:epidemiology; D017086:beta-Thalassemia / Q000097:blood / Q000517:prevention & control*
chemical_list: D006443:Hemoglobin A2