title: An algorithm to aid in the investigation of thalassemia trait in multicultural populations.
abstract: BACKGROUND
  The differentiation between iron deficiency and a thalassemia syndrome is an important consideration in the investigation of microcytic anemia.
  
  
  OBJECTIVE
  An established statistical method was used to demonstrate the importance of considering ethnic background in combination with mean cell volume (MCV) in the investigation of beta-thalassemia trait in a multicultural urban population.
  
  
  METHODS
  Posttest probabilities for beta-thalassemia trait were calculated using likelihood ratios for various microcytic MCV ranges in conjunction with published pretest probabilities for beta-thalassemia trait based on ethnic background.
  
  
  METHODS
  Regional hemoglobinopathy laboratory, St Joseph's Hospital, Hamilton, Ontario, Canada.
  
  
  METHODS
  Patient data were derived from a previously published study. The original study cohort consisted of 789 patients aged 18 years or older who had an MCV less than 80 fL and were referred for routine complete blood count during a 6-month period.
  
  
  METHODS
  Posttest probabilities.
  
  
  RESULTS
  Simplified tables for the determination of posttest probabilities for beta-thalassemia trait in individual patients based on ethnic background and MCV are provided. An algorithm to assist in determining when thalassemia investigations are indicated is presented.
  
  
  CONCLUSIONS
  A high index of suspicion based on ethnic background and low MCV can provide increased sensitivity and specificity for the detection of thalassemia trait in centers with multicultural populations similar to the study population.
authors.affiliation: University Health Network/The Princess Margaret Hospital, Toronto, Ontario, Canada.
authors.forename: T L
authors.initials: TL
authors.lastname: Kiss
authors.forename: M A
authors.initials: MA
authors.lastname: Ali
authors.forename: M
authors.initials: M
authors.lastname: Levine
authors.forename: J D
authors.initials: JD
authors.lastname: Lafferty
mesh_terms: D000465:Algorithms; D003937:Diagnosis, Differential; D004909:Erythrocyte Indices; D005006:Ethnicity; D006801:Humans; D000090463:Iron Deficiencies; D011336:Probability; D044469:Racial Groups; D012016:Reference Values; D017086:beta-Thalassemia / Q000097:blood / Q000175:diagnosis*