I’m looking for more guidance on the mapping between RDW-CV and RDW-SD. The standard code description for 21000-5 RDW-SD (fL) and 788-0 RDW-CV (%). Per LONIC search, 21000-5 is deprecated and maps to 788-0, however, their mapping guidance states, “Erythrocyte distribution width (EDW) can be reported with units of % or volume (fL). For units reported as %, use LOINC 788-0. For EDW reported in volume units, use LOINC 21000-5.” I’m trying to understand how a code based on volume (RDW-SD) is equivalent to a percentage (RDW-CV). Anyone have insight?
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