Reticulocyte count - blood

Last updated: Saturday, 01, May, 2004

MBS Online Search Page: Click here for details

Item Process
Specimen

5 mL blood in EDTA tube.

Method

Fresh blood incubated with:

  1. supravital stain for ribosomal RNA and examined by microscopy; or
  2. fluorescent dye taken up by RNA and cells counted by flow cytometry.

Some blood counters have reticulocyte modules to perform semi-automated or automated reticulocyte counts. Principle of test depends on the specific instrument.

The absolute reticulocyte count is calculated from the reticulocyte percentage and the red cell count.

Reference Interval

Term infant, cord blood: 2-6%  (microscopy)

Child, adult:     
0.2-2.0% (10-100 x 109/L)  (microscopy)
0.7-3.2% (30-140 x 109/L)  (flow cytometry).

Application

Indicated in the assessment of anaemia when bone marrow failure suspected;
apparent inadequate marrow response to haematinic therapy;
assessment of recovery after myelosuppression; and
monitoring haemolytic anaemia.

Interpretation

Reticulocyte count reflects marrow erythropoietic activity and corresponds to the finding of polychromasia on a blood film.

A low reticulocyte count in the presence of anaemia indicates bone marrow failure or haematinic deficiency.

Reference

Chin Yee I. Clin Lab Haematol 1991; 13: 177-188.