Hemoglobin Shelby interfered with the leukocyte differential channel of the Mindray BC-6800Plus hematology analyzer: a case report

Background: Hemoglobin (Hb) variants are the world's most frequent monogenic disorders; up to 150 are unstable. Mild hemolytic anemia can be the only clinical evidence that a patient has unstable Hb variants, but the minimal changes in complete blood count (CBC) are difficult to observe and often mean that the condition is undetected in most cases. Case Description: We present a report of a Hb Shelby carrier. An asymptomatic 47-year-old woman born in Bolivia was referred to our medical center for a routine health control. CBC was analyzed with a Mindray BC6800 plus counter and showed values within reference ranges. Only reticulocytosis was detected. The white blood cell differential channel showed an abnormally low fluorescent signal in the leukocyte (WBC) differential scattergram. This pattern has been observed in other counters based on similar fluorescence detection principles, linked to the presence of Hb variants, so reflect tests were performed to confirm this clinical condition. Conclusions: Incidental findings in CBC are not uncommon, an abnormal WBC scatterplot must be investigated and can be used to detect carriers in order to reach the diagnosis efficiently.