Universal screening for hemoglobinopathies in today's multi-ethnic societies: How and when

Table 3 Indicative parameters usually associated with carrier states

Carrier of	Hb	MCV	MCH	RBC	HbA2	HbF	Approximately HbS (%)	Approximately HbC (%)	Approximately HbE (%)	Approximately HbD (%)	Smear
Alpha thal	L2	L2	L2	N	N1	N					TC, APC
Beta thal	L	L	L	N or E	E4	N or E					TC, APC
HbS	N1	N1	N1	N	N3	N	45-256				Normal5
HbC	N1	N1	N1	N	N	N		45-256			TC
HbE	L-N	L-N	L-N	N	N	N or E			± 25		TC, APC
HbD	N1	N1	N1	N	N	N				± 45	Normal

¹Could be lower in case of alpha thal;

²Low depending on the form of the defect (see Table 2);

³Could be higher due to HPLC artifact;

⁴Some rare beta thal carriers have normal HbA2;

⁵Positive on sickle test;

⁶%HbS or C reduced in the presence of alpha thal. L: Low; N: Normal; E: Elevated; MCV: Mean corpuscular volume; MCH: Mean corpuscular hemoglobin; RBC: Red blood cell; TC: Target cells; APC: Anisopoikilocytosis; Hb: Hemoglobin.