Reproducibility of Manual Platelet Estimation Following Automated Low Platelet Counts

Al-Hosni, Zainab S; Al-Khabori, Murtadha; Al-Mamari, Sahimah; Al-Qasabi, Jamal; Davis, Hiedi; Al-Lawati, Hatim; Al-Riyami, Arwa Z.

doi:10.5001/omj.2016.83

Cited by 5 publications

(7 citation statements)

References 6 publications

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“…This method has the advantage of identifying platelet clumps/giant platelets/platelet satellitism or the presence of fragmented RBCs [3,[10][11][12]. In addition to the TPC, it helps in assessing additional information like platelet size, granulation, and the phenomenon of platelet aggregation and satellitism [8]. However, it has the disadvantages like marked inter-observer variability in counting the average number of platelets per OIF as noted by Nosanchuk et al and Gao et al [1,13].…”

Section: Discussionmentioning

confidence: 99%

Estimation of Total Platelet Count From Peripheral Blood Smear Needs a Correction Factor

Sahu¹,

Mohanty²,

Adhya³

2022

Cureus

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BackgroundDespite many advances in platelet counting by cell counters, the problem of falsely low or falsely high total platelet counts (TPC) is common. Many laboratories estimate platelet count on the peripheral smear to cross-check the platelet counts. However, due to the lack of a standard calculation method, discrepant results are obtained from different laboratories leading to confusion among clinicians. We aimed to formulate a standard estimation method for platelet count on peripheral smear. MethodologyIn the first step (in 100 blood samples), we determined the ratio of the TPC obtained by the automated cell counter and the total number of platelets per oil immersion field (filed size: 0.22 mm) of the corresponding blood smears. The mean of the ratios thus obtained was designated as the "multiplication factor" to be used for visual platelet count estimation on the peripheral blood smear. In the subsequent step, validation of the same was done on another 100 samples. TPC on the peripheral smears of these samples was estimated using the above "multiplication factor" and compared with the corresponding TPC obtained on the automated cell counter. ResultsThe "multiplication factor" obtained was 9.4 x 10 3 in the first set of 100 blood samples. It was used to estimate the platelet value of the second set of 100 blood samples. ConclusionsWe found an excellent agreement between the platelet counts obtained by automated cell counters and the estimation method. We suggest the multiplication factor 9.4 x 10 3 may be used with correction for microscopic field size to estimate platelet count on peripheral smears. This method is, however, not so reliable for very low platelet counts.

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Section: Discussionmentioning

confidence: 99%

Estimation of Total Platelet Count From Peripheral Blood Smear Needs a Correction Factor

Sahu¹,

Mohanty²,

Adhya³

2022

Cureus

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“…Intraclass correlation coefficient (ICC) across the four raters was 0.840 in patients with platelet count less than 1.0 lakh per cubic millimeter. 22 Lawrence et al compared triplicate automated and manual platelet counts on thrombocytopenic patients with platelet counts from 4-30×10(9)/l. The triplicate automated platelet counts differed by no more than 5×10(9)/l among themselves, whereas the manual counts varied by as much as 30×10(9)/l.…”

Section: Discussionmentioning

confidence: 99%

Comparison of platelet count by manual and automated method

Jain¹

2020

Int J Res Med Sci

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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.

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“…Giulio Bizzozero, an Italian pathologist is credited with identifying platelets as an important component of blood and their essential involvement in the mechanism of blood clotting at the end of the nineteenth century [10]. It is a well known fact that an accurate and reproducible platelet counts are of utmost importance in day-to-day clinical practice aiding not only in diagnosis but also in the treatment and prognostication of a wide variety of diseases [11]. Severe thrombocytopenia (platelet count <150 × 10 3 /µL) can present as internal and external bleeding which maybe fatal and require emergency platelet transfusion.…”

Section: Discussionmentioning

confidence: 99%

“…Mn Blood film evaluation offers added assessment of platelet size, shape, granulation, and can also be used to analyze platelet aggregation or satellitism. It is also essential for any standard of care test to be consistent, and a study carried out by Al-Hosni et al [11] demonstrated that manual platelet count estimation is reproducible in trained competent hands when a standardized methodology is used. In our study the manual methods were done independently by two observers and average values obtained were used so as to keep interobserver bias to the minimum.…”

Section: Discussionmentioning

confidence: 99%

Estimation of platelet counts: auto analyzer versus counts from peripheral blood smear based on traditional and platelet: red blood cell ratio method

Balakrishnan

Shetty

Vijaya

2018

Trop J Pathol Microbiol

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Introduction: Accurate platelet counts are of utmost importance in clinical practice The methods used for estimating platelet count are: Manual method using counting chamber, Examination of a peripheral blood smear (PBS) and automated hematology analyzers Automated hematology analyzers produce erroneous results in the presence of particles of similar size and/or light scatter like fragmented red blood cells (RBC), microcytic RBCs and in the presence of giant platelets and platelet clumps. Aims and Objectives: Comparison of platelet count by three methods: 1. Automated six part analyzer. Traditional method: Counting average platelets per ten high power fields and multiplying the same by 15,000. 3. From smear by counting the number of platelets per 1000 RBCs and calculating the platelet count on the basis of platelet: RBC ratio. Methods: Ethylene Diamine Tetra-acetic acid (EDTA) samples for platelet counts over a period of two months were analyzed by the above-mentioned methods. Statistical software SPSS 2 and independent T tests were used to compare the variables between the groups. Sensitivity and specificity of the methods was calculated. Results: 250 EDTA samples were analyzed of which normal platelet counts were (56.4%) thrombocytopenic (35.2%) and thrombocytosis (8.4%). There was no significant difference between the platelet counts done by the auto analyzer compared with traditional (P value 0.50) and platelet: RBC ratio method (0.906). Specificity of the methods was 99.1% and the sensitivity was 92.5%. Conclusion: Platelet counts by traditional and platelet: RBC ratio can be used as alternate reliable methods as compared to the auto analyzers.

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Reproducibility of Manual Platelet Estimation Following Automated Low Platelet Counts

Abstract: The agreement between different raters using manual platelet estimation was excellent. Further confirmation is necessary, with a prospective study using a gold standard method of platelet counts.

Cited by 5 publications

References 6 publications

Estimation of Total Platelet Count From Peripheral Blood Smear Needs a Correction Factor

Estimation of Total Platelet Count From Peripheral Blood Smear Needs a Correction Factor

Comparison of platelet count by manual and automated method

Estimation of platelet counts: auto analyzer versus counts from peripheral blood smear based on traditional and platelet: red blood cell ratio method

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