Method, distribution, and context

Analyzer cards must stay aligned with the analyzer family. Sysmex XN cards may list impedance for RBC/platelet counting, sodium lauryl sulfate (SLS) hemoglobin photometry after lysis, fluorescence flow cytometry for differential channels, and calculated indices from configured inputs. Beckman Coulter DxH cards may list impedance for RBC/platelet counting and VCS (volume, conductivity, scatter) for leukocyte characterization. These are method-family summaries; confirm the exact reportable result, reagent configuration, software version, and IFU locally.

Do not treat RDW-CV and RDW-SD as interchangeable. RDW-CV is a percentage derived from red-cell volume distribution relative to MCV; RDW-SD is a width in fL determined from the RBC-volume histogram at the analyzer's specified height. Their units, histogram rules, intervals, and flags differ, so no universal conversion or common cutoff is valid.

Agglutination can produce an implausibly low measured RBC count with increased calculated MCV/MCH/MCHC or analyzer flags; inspect the specimen/smear for clumps, document RBC, hemoglobin, hematocrit, and flag/histogram evidence, and follow the validated warming or repeat procedure. Lipemia can falsely increase measured photometric hemoglobin and thereby calculated MCH/MCHC; document turbidity, hemoglobin, hematocrit, and analyzer evidence, then use the locally validated interference procedure. in vitro hemolysis can affect intact-cell measurements or specimen appearance; document plasma appearance and RBC/hemoglobin/hematocrit inputs, assess specimen acceptability, and recollect when local policy identifies unacceptable hemolysis. Spherocytes are a morphology finding that can accompany increased calculated MCHC; document the smear finding with hemoglobin/hematocrit and MCHC, then follow local morphology-review criteria rather than infer an etiology from an index.