Resistance to lysis of erythrocytes containing haemoglobin C--detected in a differential white cell counting system.

Erythrocytes containing haemoglobin C do not lyse normally in the peroxidase channel of the Technicon H6000 automated cell counter. This interferes with the normal function of the channel and results in a characteristic abnormal pattern. This correlates with a reduced osmotic fragility of the red cells.