How this calculator works
A raw reticulocyte percentage can appear larger when fewer mature red cells are circulating. The hematocrit correction scales it to a chosen reference, commonly 45%. A production index then divides the corrected percentage points by an estimated maturation time. The supplied reference table gives conventional anchor values only. This page asks for the factor explicitly rather than inventing cut-offs or interpolating between those anchors. The result is an estimate for information only and is not medical advice.
Formula
Corrected reticulocytes (%) = measured reticulocytes (%) x patient Hct / reference Hct. RPI = corrected reticulocytes (percentage points) / maturation factor.
Worked example
Reticulocytes 3%, Hct 30% and reference Hct 45% give a corrected 2%. With a factor of 2, RPI is 1. Reticulocytes 6% at Hct 15% also correct to 2%; factor 2.5 gives RPI 0.8.
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Frequently asked questions
Is the corrected count a concentration?
No. This result is a corrected percentage. Use RBC concentration to calculate a true absolute reticulocyte count.
Must the reference hematocrit be 45%?
No. It is an editable convention; use the value appropriate to the laboratory or clinical method.
Why enter the maturation factor manually?
Published tables give reference values, but a unique continuous rule between them is not specified. The clinician selects the applicable factor.