A reliable screening test to identify adult carriers of the (--SEA) alpha zero-thalassemia deletion. Detection of embryonic zeta-globin chains by enzyme-linked immunosorbent assay.
Homozygous (--SEA) alpha zero-thalassemia deletion, the cause of up to 80% of fetal hydrops in Southeast Asia, is encountered in many other countries. Heterozygous carrier rates of the deletion in Southeast Asian populations range from 4% to 14%. The laboratory screening for adult carriers of (--SEA) and other alpha zero-thalassemia deletions currently rests primarily with microscopic detection of hemoglobin H inclusion bodies within erythrocytes (Hb H screen). This test is laborious and observer dependent and has poor sensitivity. We assessed a colorimetric enzyme-linked immunosorbent assay (ELISA) to detect embryonic zeta-globin chains in adult hemolysates as an alternative to detect (--SEA) alpha zero-thalassemia deletion carriers. Blood samples from 221 adults with a mean corpuscular volume less than 80 micron 3 (80 fL) were studied prospectively by currently accepted hemoglobin screening tests and ELISA. Suspected cases of alpha-thalassemia were confirmed by DNA-based diagnostics. ELISA was highly sensitive (1.0) and specific (0.94) for the detection of adult carriers of (--SEA) alpha zero-thalassemia deletion. The hemoglobin H screen had a sensitivity of 0.47 and specificity of 0.99. The zeta-globin ELISA proved simple to perform, rapid, and applicable to high volume or population-based screening programs.
Lafferty
J D
JD
Provincial Hemoglobinopathy Laboratory, Hamilton Regional Laboratory Medicine Program, McMaster University, Hamilton, Ontario, Canada.
Crowther
M A
MA
Waye
J S
JS
Chui
D H
DH
D000328:Adult; D001798:Blood Proteins / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D017353:Gene Deletion; D005820:Genetic Testing / Q000295:instrumentation / Q000379:methods*; D005914:Globins / Q000378:metabolism; D006447:Hemoglobin H / Q000378:metabolism; D006579:Heterozygote; D006801:Humans; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D017085:alpha-Thalassemia / Q000097:blood / Q000235:genetics*
D001798:Blood Proteins; C026080:plasma protein Z; D005914:Globins; D006447:Hemoglobin H