title: Overestimation of hemoglobin in a patient with an IgA-kappa monoclonal gammopathy.
abstract: A patient with multiple myeloma had an automated blood count performed on a Coulter STK-S counter that repeatedly failed internal limits for both mean corpuscular hemoglobin and mean corpuscular hemoglobin concentration. The calculated hematocrit agreed with a spun hematocrit, suggesting that the hemoglobin concentration was being overestimated by the automated counter. Measurement of the plasma hemoglobin concentration of the sample, which showed no visible hemolysis, gave a hemoglobin concentration of 32 g/L on the STK-S analyzer. Correction of the whole blood hemoglobin using the plasma hemoglobin gave a value consistent with the hematocrit. The corrected mean corpuscular hemoglobin and mean corpuscular hemoglobin concentration values were within standard limits. This patient's paraprotein was characterized as IgA-kappa and was present at a concentration of 61 g/L. The hemoglobin concentration measured on whole blood by Sysmex NE 8000 and Technicon H*1E autoanalyzers agreed reasonably well with the corrected result from the STK-S.
authors.affiliation: Department of Pathology, University of Utah Health Sciences Center, Salt Lake City, Utah, USA.
authors.forename: W L
authors.initials: WL
authors.lastname: Roberts
authors.forename: J D
authors.initials: JD
authors.lastname: Fontenot
authors.forename: C M
authors.initials: CM
authors.lastname: Lehman
mesh_terms: D000368:Aged; D001322:Autoanalysis; D001798:Blood Proteins / Q000032:analysis; D019075:Electrophoresis, Capillary; D004906:Erythrocyte Count; D005260:Female; D006400:Hematocrit; D006454:Hemoglobins / Q000032:analysis*; D006801:Humans; D007070:Immunoglobulin A / Q000097:blood*; D007145:Immunoglobulin kappa-Chains / Q000097:blood*; D007958:Leukocyte Count; D009101:Multiple Myeloma / Q000097:blood* / Q000276:immunology; D010976:Platelet Count; D015203:Reproducibility of Results
chemical_list: D001798:Blood Proteins; D006454:Hemoglobins; D007070:Immunoglobulin A; D007145:Immunoglobulin kappa-Chains