The unreliability of mean corpuscular volume and mean cellular hemoglobin determinations in the diagnosis of alpha-thalassemia in newborn infants.

Mean corpuscular volume (MCV) and mean cellular hemoglobin (MCH) were determined by means of a Hemalog 8/90 electronic counter in 51 full-term newborn infants with alpha-thalassemia-2 and 15 with alpha-thalassemia-1, as well as in 150 normal newborn infants. The mean MCV and MCH values were 92 fl +/- 06 and 33.26 pg +/- 2.22 in the normal newborn infants, 82 fl +/- 07 and 29.40 pg +/- 2.60 in the alpha-thalassemia-2 subjects, and 73 fl +/- 06 and 26.7 +/- 2.05 in the alpha-thalassemia-1 subjects. Four of the 150 normal newborn infants had MCV's < 79 fl and MCH's < 29.00 pg whereas 5 of the alpha-thalassemic subjects had MCV's > 90 fl and MCH's > 32.00 pg. We conclude that MCV and MCH determinations are unreliable in the diagnosis of alpha-thalassemia in the neonatal period.