title: Erythrocyte protoporphyrin or hemoglobin: which is a better screening test for iron deficiency in children and women?
abstract: BACKGROUND
  Hemoglobin and erythrocyte protoporphyrin (EP) tests are commonly used to screen for iron deficiency. However, little research has been done to systematically evaluate the sensitivity and specificity of these 2 tests.
  
  
  OBJECTIVE
  The objective of this study was to evaluate the sensitivity and specificity of hemoglobin and EP measurements in predicting iron deficiency in preschool children and in women of childbearing age.
  
  
  METHODS
  We examined data from the third National Health and Nutrition Examination Survey (n = 2613 children aged 1-5 y and n = 5175 nonpregnant women aged 15-49 y). Children or women with blood lead >or= 10 microg/dL were excluded from this study. We used the receiver operating characteristic (ROC) curve to characterize the sensitivity and specificity of hemoglobin and EP measurements in screening for iron deficiency, defined as having abnormal values for >or= 2 of the following 3 indexes: mean cell volume, transferrin saturation, and serum ferritin.
  
  
  RESULTS
  The ROC performance of EP was consistently better than that of hemoglobin for detecting iron deficiency in preschool children. However, in nonpregnant women, we found no significant difference between EP and hemoglobin in ROC performance for detecting iron deficiency. We observed the same results when we stratified the analyses by sex and race of the children and by race of the women.
  
  
  CONCLUSIONS
  For children aged 1-5 y, EP is a better screening tool for iron deficiency than is hemoglobin. However, for nonpregnant women, EP and hemoglobin have similar sensitivity and specificity for predicting iron deficiency.
authors.affiliation: Division of Nutrition and Physical Activity, Centers for Disease Control and Prevention, Atlanta, GA 30341, USA. zmei@cdc.gov
authors.forename: Zuguo
authors.initials: Z
authors.lastname: Mei
authors.forename: Ibrahim
authors.initials: I
authors.lastname: Parvanta
authors.forename: Mary E
authors.initials: ME
authors.lastname: Cogswell
authors.forename: Elaine W
authors.initials: EW
authors.lastname: Gunter
authors.forename: Laurence M
authors.initials: LM
authors.lastname: Grummer-Strawn
mesh_terms: D000293:Adolescent; D000328:Adult; D018798:Anemia, Iron-Deficiency / Q000097:blood / Q000175:diagnosis*; D002675:Child, Preschool; D004909:Erythrocyte Indices; D004912:Erythrocytes / Q000737:chemistry; D005260:Female; D005293:Ferritins / Q000097:blood; D006454:Hemoglobins / Q000032:analysis*; D006801:Humans; D007223:Infant; D008297:Male; D008403:Mass Screening; D008875:Middle Aged; D009749:Nutrition Surveys; D011237:Predictive Value of Tests; D011524:Protoporphyrins / Q000032:analysis / Q000097:blood*; D012372:ROC Curve; D012680:Sensitivity and Specificity; D014481:United States
chemical_list: D006454:Hemoglobins; D011524:Protoporphyrins; D005293:Ferritins