Introduction: Many diseases such as malaria, dengue, pyrexia of unknown origin, pregnancy-induced hypertension are associated with low platelet counts. Automated method is the most reliable method. It is simple, fast, and most widely used. But automated cell counters are not available at underresourced laboratories, especially in rural settings. Hence, platelet estimation by peripheral blood smear is more easy and cost-effective.

Aim: To compare platelet count estimation performed by the peripheral blood smear method and the automated cell counter method. 

Objective: Peripheral Blood smear examination acts as a good quality control tool in assessing the results produced by the automated cell counter.

Materials and Methods: Present study was carried out in the Department of Pathology at a tertiary care centre in rural Haryana. Study included 95 random blood samples collected into ethylenediaminetetraacetic acid. These were examined by both peripheral blood smear and automated cell counter for platelet estimation.

Results: In the present study there was no significant (p = 0.866) difference of values between manual peripheral blood smear (PBS) method (platelets average per 100x, multiplied by 15.0x109/L) of platelet estimation (1.90±0.97 lacs/mm3) when compared with that of automated cell counter platelet value (1.88 lacs/ mm3±0.98). Significant positive correlation between the result of both methods (r=0.996, p=0.0001) was observed when samples were analysed by Pearson correlation test.

Conclusion: Although the necessity of automated cell counters for rapid generation of results of vast number of blood samples is undeniable, yet the results of peripheral blood smear platelet estimation are comparable with them. Hence manual smear examination serves as a quality control tool in assessing the results of the automated cell counters.

Keywords: Automated Method; Manual Method; Peripheral Blood Smear; Platelet Count.