Incidental finding of rare hemoglobin: hemoglobin Bari in northeast Spain.

OBJECTIVES: Cation exchange high-performance liquid chromatography (HPLC) is one of the techniques available for determining glycated hemoglobin (HbA1c ) and also the method of choice for structural hemoglobinopathies screening. The objective of this case is to show how in a routine HbA1c test it is possible to incidentally find a hemoglobinopathy.

CASE PRESENTATION: In a routine blood analysis, an abnormal value for the hemoglobin A2 (HbA2 ) was obtained during the study of HbA1c with HPLC on the ADAMS™ A1c HA-8180T. After suspecting it could be due to the presence of a hemoglobinopathy, the study of possible variants was expanded using electrophoresis and HPLC on the Hydrasys and Variant II analysers, respectively. Since it could not be identified by these conventional methods, a genetic study was also carried out using Sanger sequencing. The patient presented a low HbA2  (1.3 %) and a 24.9 % variant with a retention time of 1.95 min, compatible with alpha-globin chain variant. In the genetic study, the pathogenic variant c.138C>G was detected in the  HbA 2  gene in heterozygosis, which resulted in the expression of the structural hemoglobinopathy known as hemoglobin Bari.

CONCLUSIONS: The initial screening for structural hemoglobinopathies allows its identification or suspicion especially when it was performed with HbA1c analysis, requiring subsequent confirmation and diagnosis by other techniques.