A novel method to estimate platelet counts from peripheral smears: A study comparing a new method of platelet estimation with existing methods.
Keywords:
Platelet, Platelet count, Thrombocytopenia, Hematology
Abstract
Background: Automated hematology analyzers have a low degree of accuracy in predicting platelet counts in patients with thrombocytopenia. Hence automated platelet counts should be crosschecked by reviewing the peripheral blood smear in cases of thrombocytopenia. However existing methods for platelet count estimation from peripheral blood smears have certain drawbacks. Hence we suggest a new method to estimate platelet count from peripheral smear and compared it with the existing methods. Methods: Platelet count was estimated by four different methods in 200 blood samples and compared with the platelet count obtained from automated analyzer Sysmex XT-1800i. Method A was based on the platelet/Red Blood cell (RBC) ratio in ten oil immersion fields and multiplying it by total RBC count, Methods B, C and D were based on the average number of platelets per oil immersion field. Platelet count was obtained by multiplying by 15000 in Method B, by 20000 in Method C, by hemoglobin value X 1000 in Method D. Results were analyzed by ANOVA, student’s t test and correlation coefficient.Result: Results of Method A had a strong correlation with the automated blood counts (0.973). The results were not significantly different from the automated blood counts (p value of 0.798). Results of other methods were significantly different from automated platelet counts (p<0.05).Conclusion: Platelet count estimation based on platelet/RBC ratio in ten oil immersion fields and total RBC count is a simple and reliable method to estimate platelet counts from peripheral smears. DOI: 10.21276/apalm.2017.1159References
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2. Marionneaux S, Francisco N, Chan V, Hanenberg J, Rafael J, Chua C, et al. Comparison of automated platelet counts and potential effect on transfusion decisions in cancer patients. Am J Clin Pathol. 2013;140(5):747–54.
3. 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.
4. Nosanchuk JS, Chang J, Bennett JM. The analytic basis for the use of platelet estimates from peripheral blood smears. Laboratory and clinical applications. Am J Clin Pathol. 1978;69(4):383–7.
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6. Segal HC, Briggs C, Kunka S, Casbard A, Harrison P, Machin SJ, et al. Accuracy of platelet counting haematology analysers in severe thrombocytopenia and potential impact on platelet transfusion. Br J Haematol. 2005;128(4):520–5.
7. Kunz D. Possibilities and limitations of automated platelet counting procedures in the thrombocytopenic range. Semin Thromb Hemost. 2001;27(3):229–35.
8. Brahimi M, Osmani S, Arabi A, Enta-Soltane B, Taghezout Z, Elkahili 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.
9. Lin J, Luo Y, Yao S, Yan M, Li J, Ouyang W, et al. Discovery and Correction of Spurious Low Platelet Counts due to EDTA-Dependent Pseudothrombocytopenia. J Clin Lab Anal. 2015;29(5):419–26.
10. Latif S, Veillon DM, Brown D, Kaltenbach J, Curry S, Linscott AJ, et al. Spurious automated platelet count. Enumeration of yeast forms as platelets by the cell-DYN 4000. Am J Clin Pathol. 2003;120(6):882–5.
11. Boulassel M-R, Al-Farsi R, Al-Hashmi S, Al-Riyami H, Khan H, Al-Kindi S. Accuracy of Platelet Counting by Optical and Impedance Methods in Patients with Thrombocytopaenia and Microcytosis. Sultan Qaboos Univ Med J. 2015;15(4):e463–8.
12. Oliveira RAG, Takadachi MM, Nonoyama K, Barretto OC de O. Is automated platelet counting still a problem in thrombocytopenic blood? Sao Paulo Med J. 2003;121(1):19–23.
13. Harrison P, Segal H, Briggs C, Murphy M, Machin S. Impact of immunological platelet counting (by the platelet/RBC ratio) on haematological practice. Cytometry B Clin Cytom. 2005;67(1):1–5.
14. Abid BF. Estimation of Platelet Count on the Basis of Red cell: Platelet Ratio. Iraqi Journal of Medical Sciences. 2009;7(3):40-5
15. Gao Y, Mansoor A, Wood B, Nelson H, Higa D, Naugler C. Platelet count estimation using the CellaVision DM96 system. J Pathol Inform. 2013;4:16.
16. Bajpai R, Rajak C, Poonia M. Platelet estimation by peripheral smear: Reliable, rapid, cost effective method to assess degree of thrombocytopenia. International Journal of Medical Science Research and Practice 2015;2(2):90-93
17. Torres SL, Velez EL. Platelet verification under microscope calculated by the patient’s hemoglobin factor. Laboratory Medicine 2004;7:430-3
18. 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.
2. Marionneaux S, Francisco N, Chan V, Hanenberg J, Rafael J, Chua C, et al. Comparison of automated platelet counts and potential effect on transfusion decisions in cancer patients. Am J Clin Pathol. 2013;140(5):747–54.
3. 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.
4. Nosanchuk JS, Chang J, Bennett JM. The analytic basis for the use of platelet estimates from peripheral blood smears. Laboratory and clinical applications. Am J Clin Pathol. 1978;69(4):383–7.
5. Webb DI, Parker L, Webb K. Platelet count assessment from peripheral blood smear (PBS). Alaska Med. 2004;46(4):92–5.
6. Segal HC, Briggs C, Kunka S, Casbard A, Harrison P, Machin SJ, et al. Accuracy of platelet counting haematology analysers in severe thrombocytopenia and potential impact on platelet transfusion. Br J Haematol. 2005;128(4):520–5.
7. Kunz D. Possibilities and limitations of automated platelet counting procedures in the thrombocytopenic range. Semin Thromb Hemost. 2001;27(3):229–35.
8. Brahimi M, Osmani S, Arabi A, Enta-Soltane B, Taghezout Z, Elkahili 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.
9. Lin J, Luo Y, Yao S, Yan M, Li J, Ouyang W, et al. Discovery and Correction of Spurious Low Platelet Counts due to EDTA-Dependent Pseudothrombocytopenia. J Clin Lab Anal. 2015;29(5):419–26.
10. Latif S, Veillon DM, Brown D, Kaltenbach J, Curry S, Linscott AJ, et al. Spurious automated platelet count. Enumeration of yeast forms as platelets by the cell-DYN 4000. Am J Clin Pathol. 2003;120(6):882–5.
11. Boulassel M-R, Al-Farsi R, Al-Hashmi S, Al-Riyami H, Khan H, Al-Kindi S. Accuracy of Platelet Counting by Optical and Impedance Methods in Patients with Thrombocytopaenia and Microcytosis. Sultan Qaboos Univ Med J. 2015;15(4):e463–8.
12. Oliveira RAG, Takadachi MM, Nonoyama K, Barretto OC de O. Is automated platelet counting still a problem in thrombocytopenic blood? Sao Paulo Med J. 2003;121(1):19–23.
13. Harrison P, Segal H, Briggs C, Murphy M, Machin S. Impact of immunological platelet counting (by the platelet/RBC ratio) on haematological practice. Cytometry B Clin Cytom. 2005;67(1):1–5.
14. Abid BF. Estimation of Platelet Count on the Basis of Red cell: Platelet Ratio. Iraqi Journal of Medical Sciences. 2009;7(3):40-5
15. Gao Y, Mansoor A, Wood B, Nelson H, Higa D, Naugler C. Platelet count estimation using the CellaVision DM96 system. J Pathol Inform. 2013;4:16.
16. Bajpai R, Rajak C, Poonia M. Platelet estimation by peripheral smear: Reliable, rapid, cost effective method to assess degree of thrombocytopenia. International Journal of Medical Science Research and Practice 2015;2(2):90-93
17. Torres SL, Velez EL. Platelet verification under microscope calculated by the patient’s hemoglobin factor. Laboratory Medicine 2004;7:430-3
18. 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.
Published
2017-02-19
Issue
Section
Original Article
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