Hereditary membranopathies are important red blood cell (RBC) disorders, however, diagnosis can be challenging in mild cases for which osmotic fragility tests yield normal results. The diagnostic gold standard under these conditions is osmotic gradient ektacytometry. Since the diagnosis of hereditary membranopathies influences patient management, a screening test might be of value.
Design and Methods
Since the percentage of hyperchromic RBCs is routinely measured by many hematologic laboratories, we evaluated the predictive value of an elevated percentage of hyperchromic RBCs for the detection of RBC disorders. We did an extensive workup of all patients undergoing standard hematogram during a period of six months at our institution with a fraction of hyperchromic RBC larger than 10% by reviewing the medical history and performing osmotic
32’226 individuals were screened of which 162 (0.5%) showed more than 10% hyperchromic RBC. All of these patients which could be examined by ektatocytometry showed abnormal membrane deformability. Hereditary spherocytosis (HS) was found in a third of these patients, in most cases unknown to the patient and currently asymptomatic. Another 17.9% of the patients with an elevated subpopulation of hyperchromic RBC suffered from a known viral infection (HIV, Hepatitis).
Our study shows that a proportion of hyperchromic erythrocytes larger than 10% is associated with RBC membrane disorders in a third of patients and further follow up should be considered.