Identification of a rare variant haemoglobin (Hb Sinai-Baltimore) causing spuriously low haemoglobin A(1c) values on

Geoff Smith1, Heather Murray, Stephen O Brennan

  • 1Clinical Biochemistry Department, Southern Community Laboratories, 3rd Floor, Clinical Services Building, Dunedin Hospital, 201 Great King Street, Dunedin 9016, New Zealand. geoff.smith@sclabs.co.nz

Commonly used methods for assay of haemoglobin A(1c) (HbA(1c)) are susceptible to interference from the presence of haemoglobin variants. In many systems, the common variants can be identified but scientists and pathologists must remain vigilant for more subtle variants that may result in spuriously high or low HbA(1c) values. It is clearly important to recognize these events whether HbA(1c) is being used as a monitoring tool or, as is increasingly the case, for diagnostic purposes. We report a patient with a rare haemoglobin variant (Hb Sinai-Baltimore) that resulted in spuriously low values of HbA(1c) when assayed using ion exchange chromatography, and the steps taken to elucidate the nature of the variant.