Failure of ouabain to influence the osmotic fragility in hereditary spherocytosis.

No effect of 3 mumol ouabain on the osmotic fragility of red blood cells in subjects suspected of being carriers of hereditary spherocytosis, as well as in patients with overt disease could be demonstrated. These results are in disagreement with a recent report. Some possible explanations for these discrepant results are discussed. It is concluded that ouabain probably adds little to the diagnostic capability of the osmotic fragility test.