title: Differential diagnosis of microcytic anemia: the role of microcytic and hypochromic erythrocytes.
abstract: BACKGROUND
  Various indices derived from red blood cell (RBC) parameters have been described for distinguishing thalassemia and iron deficiency. We studied the microcytic to hypochromic RBC ratio as a discriminant index in microcytic anemia and compared it to traditional indices in a learning set and confirmed our findings in a validation set.
  
  
  METHODS
  The learning set comprised samples from 371 patients with microcytic anemia mean cell volume (MCV < 80 fL), which were measured on a CELL-DYN Sapphire analyzer and various discriminant functions calculated. Optimal cutoff values were established using ROC analysis. These values were used in the validation set of 338 patients.
  
  
  RESULTS
  In the learning set, a microcytic to hypochromic RBC ratio >6.4 was strongly indicative of thalassemia (area under the curve 0.948). Green-King and England-Fraser indices showed comparable area under the ROC curve. However, the microcytic to hypochromic ratio had the highest sensitivity (0.964). In the validation set, 91.1% of microcytic patients were correctly classified using the M/H ratio.
  
  
  CONCLUSIONS
  Overall, the microcytic to hypochromic ratio as measured in CELL-DYN Sapphire performed equally well as the Green-King index in identifying thalassemia carriers, but with higher sensitivity, making it a quick and inexpensive screening tool.
authors.affiliation: Hematology Laboratory, Hospital Galdakao - Usansolo, Galdakao, Spain.
authors.forename: E
authors.initials: E
authors.lastname: Urrechaga
authors.forename: J J M L
authors.initials: JJ
authors.lastname: Hoffmann
authors.forename: S
authors.initials: S
authors.lastname: Izquierdo
authors.forename: J F
authors.initials: JF
authors.lastname: Escanero
mesh_terms: D000747:Anemia, Hypochromic / Q000097:blood* / Q000175:diagnosis* / Q000209:etiology; D018798:Anemia, Iron-Deficiency / Q000097:blood* / Q000175:diagnosis*; D003937:Diagnosis, Differential; D004909:Erythrocyte Indices; D006801:Humans; D012372:ROC Curve; D017086:beta-Thalassemia / Q000097:blood / Q000175:diagnosis
keywords: Anemia; erythrocytes; hypochromic; iron deficiency; microcytic; thalassemia