An unstable haemoglobin, Hb Tacoma beta30 (B12) arg leads to ser, detected at birth by the demonstration of red cell inclusions.

Incomplete expression of human haemoglobin beta-chains at birth may lead to difficulty in the early demonstration of an inherited beta-chain variant. In this case, the rare unstable variant, Hb Tacoma beta30 (B12) arg leads to ser, although not present in cord blood in sufficient amounts to be easily detected by routine electrophoretic techniques, was readily shown to be present by the striking inclusions provoked by prolonged incubation of the neonatal red cells with new methylene blue.