Temporal trends in reticulocyte count with Methylene blue staining: A comparative study to assess reliability of reticulocyte count as a quality control parameter

Introduction: The New Methylene Blue method for staining reticulocytes was introduced by Brecher1 in 1949. This method has found wide acceptance. It is recommended for reticulocyte counting. Although there is no literature on the exact interaction allowing staining to take place, it has been suggested that New Methylene Blue localizes at a ribosomal site. By the new methylene-blue method normal reticulocyte count ranges from 0.5 to 2.5%.

Aim: To study Variation in reticulocyte count and staining quality of blood smears stained by New methylene blue over four weeks.

Methods: 50 EDTA anti-coagulated blood specimens were collected by simple random sampling. Reticulocyte count were determined by the new methylene-blue method weekly for four weeks and statistical analysis done by Paired t-test.

Results: Total number of 50 cases in our department were assessed. Ages ranged from 8 to 85 years. Mean age is 46.5 years +/- a standard deviation of 19.5 years. Total twenty eight male (56%) and 22(44%) female patients were studied. Mean retic value on day 1 is 1.6 %, day 8 is 1.4 %, day 15 is 1.1 % and day 21 is 0.87 %.

Conclusions: The mean retic count of the samples had decreased to 0.874 on day 21 when compared with 1.6 on day 1. The difference in mean retic count was highly statistically significant as per paired t- Test (P<0.01). Therefor reticulocyte count may not be reliable as a quality control parameter for external quality assurance programe.