Comparison of platelet count by manual and automated method

Dileep Kumar Jain


Background: Since the emergence of dengue fever in the past few years, platelet count has become a routine test in every pathology lab. Common methods are by peripheral blood smears made from blood collected in ethylenediaminetetraacetic acid (EDTA) tubes, by neubaeur chamber, automated method by hematology cell counter.

Methods: Blood samples of 460 adult patients and 72 children (<15 years), including indoor and outdoor, between May to August 2019, attending Hind institute of medical sciences, were collected in EDTA tubes. Samples were properly mixed on blood shaker and immediately peripheral blood smears were made and stained with Leishman stain. Platelet count of every sample was done by peripheral blood smear and by Mindray (BC5150) automated cell counter, simultaneously.

Results:  Results by manual slide method are slightly higher than automated method but significantly not different from automated method.

Conclusions: Traditional slide method can also be used if done carefully comparable to automated method especially useful in small labs which can’t afford automated cell counter.


Platelet count, Manual, Automated, Cell counter, Peripheral blood smear

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Afzal MM, Indira V, Colonel DR. Role of peripheral blood smear examination and manual platelet counts as an adjunct to automated platelet count. MRIMS J Health Sci. 2019;7(3):81-4.

Campbell NA. Platelets are pinched-off cytoplasmic fragments of specialized bone marrow cells. In: Cain M, Minorsky P, Reece J, Urry L, Wasserman eds. Biology. 8th edn. London: Pearson; 2008.

Anchinmane VT, Sankhe SV. Utility of peripheral blood smear in platelet count estimation. Int J Res Med Sci. 2019;7:434-7.

Becton-Dickinson. Unopette WBC/Platelet determination for manual methods. Rutherford, N.J.: Becton, Dickinson, and Company; 1996: 2.

Véronique B, Geneviève F, Jacqmin H, Bernard C, Sandrine G, Soraya W, et al. Platelet counting: ugly traps and good advice. Proposals from the French-speaking cellular hematology group. J Clin Med. 2020;9:808.

Imoru M. Determination of platelet and white blood cell counts from peripheral blood smear: an indispensable method in under-resourced laboratories. Int Blood Res Rev. 2016;5(2):1-7.

International council for standardization in haematology expert panel on cytometry; International society of laboratory hematology task force on platelet counting. Platelet counting by the RBC/platelet ratio method. A reference method. Am J Clin Pathol. 2001;115(3):460-4.

Chakrabarti I. Platelet satellitism: a rare, interesting, in vitro phenomenon. Indian J Hematol Blood Transfus. 2014;30(3):213-4.

Zandecki M, Genevieve F, Gerard J, Godon A. Spurious counts and spurious results on haematology analysers: a review. Part I: platelets. Int J Lab Hematol. 2007;29(1):4-20.

De la Salle BJ, McTaggart PN, Briggs C, Harrison P, Dore CJ, Lonair I, et al. The accuracy of platelet counting in thrombocytopenic blood samples distributed by the UK National external quality assessment scheme for general haematology. Am J Clin Pathol. 2012;137(1):65-74.

Kolawole F, Okogun G, Omisakin C, Adeyemi A, Ayodele E. Modified Leishman Stain: The Mystery Unfolds. British Journal of Medicine and Medical Research. 2014;4:4591-4606.

Asim M, Rame K, Mansour H, Bayan Z, Hala S, Ngah D, et al. Platelet count; automated vs manual estimation on blood smear Prince Rashid hospital, RMS. Int J Biol Med Res. 2015;6(3):5148-50.

Castromayor APA, Cadete J, Agreda L. Comparison between manual and automated platelet counts of adult patients with thrombocytopenia at St. Paul's hospital Iloilo (SPHI), Philippines. HemaSphere. 2019;3(S1):1005.

Anitha K, Itagi I, Itagi V. Compasrison of platelet count by peripheral smear method and automated method in pregnant women. Natl J Physiol Pharm Pharmacol. 2014;4:39-42.

Bajpai R, Rajak C, Poonia M. Platelet estimation by peripheral smear: Reliable, rapid, cost effective method to assess degree of thrombocytopenia. Inter J Medical Sci Prac. 2015;2(2):90-93.

Mohamed-Rachid B, Raya AF, Sulaiman AH, Salam AK. Comparative analysis of four methods for enumeration of platelet counts in thrombocytopenic patients. J Appl Hematol. 2015;6: 119-24.

Malok M, Titchener EH, Bridgers C, Lee BY, Bamberg R. Comparison of two platelet count estimation methodologies for peripheral blood smears. Clin Lab Sci. 2007;20(3):154-60.

Balakrishnan A, Shetty A, Vijaya C. Estimation of platelet counts: auto analyzer versus counts from peripheral blood smear based on traditional and platelet: red blood cell ratio method. Tropical J Pathol Microbiol. 2018;4 (5):389-95.

Webb DI, Parker L, Webb K. Platelet count assessment from peripheral blood smear (PBS). Alaska Medicine. 2004;46(4):92-5.

Brahimi M, Osmani S, Arabi A, Soltane B, Taghezout Z, Elkhaili BS, et al. The estimation of platelet count from a blood smear on the basis of the red cell: platelet ratio. Turk J Haematol. 2009;26(1): 21-4.

Lazreg H, Benaoum MN, Adda A, Brahimi M. Which method is the best for estimating platelet count?. Natl J Physiol Pharm Pharmacol. 2014;4: 177-78.

Al-Hosni ZS, Al-Khabori M, Al-Mamari S, Al-Qasabi J, Davis H, Al-Lawati H, et al. reproducibility of manual platelet estimation following automated low platelet counts. Oman Med J. 2016;31(6):409-13.

Lawrence JB, Yomtovian RA, Dillman C, Masarik SR, Chongkolwatana V, Creger, RJ, et al. Reliability of automated platelet counts: comparison with manual method and utility for prediction of clinical bleeding. Am J Hematol. 1995;48:244-50.