Diagnostic value of zinc protoporphyrin in a screening strategy for alpha-thalassemia.
The definitive diagnosis of alpha-thalassemia involves detection of a deletion of one or more alpha-globin that encode the alpha-chains of Hb (hemoglobin). To determine whether DNA analysis is indicated, screening tests such as mean corpuscular volume (MCV) and Hb typing are employed. alpha-Thalassemia often correlates with normal or low HbA2 values. Zinc protoporphyrin (ZPP) is usually high in ferropenic anemia or lead-poisoning and is normal or slightly raised in beta-thalassemia. Therefore, ZPP is currently used as a marker to discriminate between ferropenic anemia and beta-thalassemia. We investigated the diagnostic potential of ZPP < 150 micromol/mol heme in a screening strategy for alpha-thalassemia. We measured ZPP and performed DNA analysis for detecting the seven most prevalent alpha-thalassemia deletions, namely, alpha3.7, SEA, alpha20.5, alpha4.2, MED, FIL, and THAI, in the blood samples of 200 patients with MCV < 70 fL and HbA2 < or = 3.5%. Deletions were detected in 9% subjects in the ZPP > or = 150 group (n = 175) and 56% subjects in the ZPP < 150 group (n = 29); this difference was statistically significant (chi-square test, P < 0.001). We conclude that ZPP < 150 micromol/mol heme can be used in a new screening strategy for alpha-thalassemia.
Sardón Estévez
Nadia
N
Medial Medisch-Diagnostische Laboratoria, Haarlem, The Netherlands. nadia_sardon_estevez@hotmail.com
Herruer
Martinus H
MH
Jansen
Ruud
R
Bergkamp
Ferry J M
FJ
Gorgels
Jozef P M C
JP
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood; D002648:Child; D002675:Child, Preschool; D005260:Female; D005914:Globins / Q000235:genetics; D006443:Hemoglobin A2 / Q000032:analysis; D006801:Humans; D007223:Infant; D008297:Male; D008403:Mass Screening / Q000379:methods; D008875:Middle Aged; D011524:Protoporphyrins / Q000097:blood*; D017384:Sequence Deletion; D055815:Young Adult; D017085:alpha-Thalassemia / Q000175:diagnosis*
D015415:Biomarkers; D011524:Protoporphyrins; C017803:zinc protoporphyrin; D005914:Globins; D006443:Hemoglobin A2