Comparative evaluation of platelet counts in two hematology analyzers and potential effects on prophylactic platelet transfusion decisions

Application of image recognition technology in pathological diagnosis of blood smears

Traditional manual blood smear diagnosis methods are time-consuming and prone to errors, often relying heavily on the experience of clinical laboratory analysts for accuracy. As breakthroughs in key technologies such as neural networks and deep learning continue to drive digital transformation in the medical field, image recognition technology is increasingly being leveraged to enhance existing medical processes. In recent years, advancements in computer technology have led to improved efficiency in the identification of blood cells in blood smears through the use of image recognition technology. This paper provides a comprehensive summary of the methods and steps involved in utilizing image recognition algorithms for diagnosing diseases in blood smears, with a focus on malaria and leukemia. Furthermore, it offers a forward-looking research direction for the development of a comprehensive blood cell pathological detection system.

Performance evaluation of PLT-H (hybrid-channel platelet) under various interferences and application studies for platelet transfusion decisions

The hybrid-channel platelet counting method (PLT-H) is a new platelet counting technique proposed by Mindray of China. In this study, we aimed to evaluate the accuracy of this technique in various situations and its reliability in platelet transfusion decision-making. A total of 378 venous blood samples were tested. Using the immunological PLT counting method recommended by the International Council for Standardization in Hematology as the reference method (PLT-IRM), Passing-Bablok regression and Bland-Altman analysis were performed on the PLT-H results. The anti-interference performance of PLT-H under different interference levels was explored using intergroup comparisons, and confusion matrices were analyzed at various transfusion cutoff values. In the absence of interference, there was a strong correlation between PLT-H and PLT-IRM (r = 0.993, 95% CI: 0.990-0.996). Under various interference conditions, the correlation between PLT-H and PLT-IRM was between 0.963 and 0.992, with an average deviation of -14.56 to -2.02. The performance of PLT-H against interference did not change significantly with increasing levels of small RBCs, large PLTs, and RBC fragments (P = .5704, 0.0832, 0.9893). In low-value samples (PLT <100 × 109/L), the coefficient of variation (CV) for PLT-H was less than 7.6%, regardless of the presence or absence of interfering substances. In addition, there was a high agreement between PLT-H and PLT-IRM (ICC = 0.972). Confusion matrice analysis at each medical decision level showed similarity to methods using the fluorescence channel (PLT-O) and superiority to the impedance channel (PLT-I). Compared with PLT-I, PLT-H has higher accuracy in PLT counting, stronger anti-interference ability, better performance in low-value samples at no extra economic cost and can be more useful for platelet transfusion decision-making. PLT-H is a novel method for platelet counting that offers higher accuracy, providing physicians with the ability to make better medical decisions, particularly in cases where values are low, or interference is present. As it does not require additional reagents, it is highly likely to replace PLT-I and become the mainstream method for platelet counting in the future.

Feasibility of a mean platelet volume standard: an international council for standardization in hematology (ICSH) inter-laboratory study

We have evaluated a commercial-fixed porcine platelet preparation (with and without added fixed human red blood cells (RBC)) for the potential standardization of mean platelet volume (MPV) measurements. The standards (Biotechne) were distributed internationally to 19 laboratories including all major hematology instrument manufacturers and academic/pathology laboratories. Overall, the standards demonstrated excellent stability up to 1 month within both MPV values and platelet counts when stored at 4°C. The presence of RBC significantly increased the platelet count and MPV values compared to platelets alone. However, as expected, there were differences in MPV values between different instruments and manufacturers. MPV values were also significantly higher in the whole blood standard compared to the platelet standard in the majority of instruments except with some instruments, where MPV values were significantly higher in the platelet only preparation. To further investigate this phenomenon, two different Platelet MPV preparations (with low and high MPV) in combination with 3 different RBC MCV preparations (with low, normal or high MCVs) were tested to try and further elucidate how RBC populations may impact upon platelet analysis (count, MPV, and PDW) using a single impedance analyzer. Both MPV and MCV values showed good stability over the course of the study for up to 50 days. As expected, the RBC preparation with the lowest MCV had the greatest impact on the MPV. However, this was not observed with an increase in MCV of the RBC or by a larger MPV of the platelet population. To further understand how different gating strategies may also influence results, we investigated the effect of either fixed or floating gate strategies upon MPV raw data from patient samples in a single impedance analyzer. Overall, it was clear that floating and fixed gate strategies also significantly impact upon MPV values. In conclusion, we have demonstrated the potential of an MPV standard with good stability characteristics for calibrating and comparing full blood counters that use different analysis principles, gating and MPV calculations. This may facilitate future instrument calibration and harmonization of results between different technologies.

Alinity hq platelet count is not impacted by severe microcytosis

Background

Impedance technology has been shown to overestimate platelet (PLT) count in samples with microcytes, while the optical‐fluorescence PLT count (PLT‐F) by Sysmex has been suggested to be unaffected by microcytosis. The Abbott Alinity hq analyzer employs multi‐dimensional optical PLT counting. Our goal was to assess the accuracy of this technology in microcytic samples.

Methods

Platelet measurements were performed by Alinity hq and the impedance (PLT‐I) and PLT‐F methods on a Sysmex XN‐3000 analyzer on 464 samples. PLT concentration range was 6.56–947 × 10⁹/L and mean cell volume (MCV) 40.9–123.0 fL. Samples were categorized into normocytic (MCV > 80 fL), microcytic (MCV 65–80 fL), and severely microcytic (MCV < 65 fL) groups.

Results

Alinity hq PLT count showed excellent agreement with PLT‐F (r = 1.00). Sysmex PLT‐I data showed somewhat weaker correlation with both PLT‐F and Alinity hq (r = 0.98). Increasing bias between Sysmex PLT‐I and PLT‐F was seen with decreasing MCV values, with mean bias of 35.2 × 10⁹/L in severe microcytosis. An inverse relationship was demonstrated between the PLT‐I versus PLT‐F bias and MCV (p < 0.0001). Consistent mean bias was observed between Alinity hq and PLT‐F across all MCV ranges.

Mean platelet volume was suppressed or flagged by Sysmex XN in 50% of the samples in the severely microcytic group, and markedly higher red cell distribution width (RDW) was reported compared to Alinity hq (18.1% vs 13.7%, p < 0.0001).

Conclusion

The Sysmex PLT‐I method overestimated the PLT count in samples with severe microcytosis. Alinity hq provided PLT counts and PLT and RBC indices that were not impacted by microcytosis.

Performance of Platelet Counting in Thrombocytopenic Samples: Comparison between Mindray BC-6800Plus and Sysmex XN-9000

The performance of platelet (PLT) counting in thrombocytopenic samples is crucial for transfusion decisions. We compared PLT counting and its reproducibility between Mindray BC-6800Plus (BC-6800P, Mindray, Shenzhen, China) and Sysmex XN-9000 (XN, Sysmex, Kobe, Japan), especially focused on thrombocytopenic samples. We analyzed the correlation and agreement of PLT-I channels in both analyzers and BC-6800P PLT-O mode and XN PLT-F channel in 516 samples regarding PLT counts. Ten thrombocytopenic samples (≤2.0 × 10⁹/L by XN PLT-F) were measured 10 times to investigate the reproducibility with the desirable precision criterion, 7.6%. The correlation of BC-6800P PLT-I and XN PLT-I was arranged moderate to very high; but the correlation of BC-6800P PLT-O and XN PLT-F was arranged high to very high. Both BC-6800P PLT-I vs. XN PLT-I and BC-6800P PLT-O vs. XN PLT-F showed very good agreement (κ = 0.93 and κ = 0.94). In 41 discordant samples between BC-6800P PLT-O and XN PLT-F at transfusion thresholds, BC-6800P PLT-O showed higher PLT counts than XN-PLT-F, except the one case. BC-6800P PLT-O exceeded the precision criterion in one of 10 samples; but XN PLT-F exceeded it in six of 10 samples. BC-6800P would be a reliable option for PLT counting in thrombocytopenic samples with good reproducibility.

Advances in understanding the pathogenesis of hereditary macrothrombocytopenia

Low platelet count, or thrombocytopenia, is a common haematological abnormality, with a wide differential diagnosis, which may represent a clinically significant underlying pathology. Macrothrombocytopenia, the presence of large platelets in combination with thrombocytopenia, can be acquired or hereditary and indicative of a complex disorder. In this review, we discuss the interpretation of platelet count and volume measured by automated haematology analysers and highlight some important technical considerations relevant to the analysis of blood samples with macrothrombocytopenia. We review how large cohorts, such as the UK Biobank and INTERVAL studies, have enabled an accurate description of the distribution and co-variation of platelet parameters in adult populations. We discuss how genome-wide association studies have identified hundreds of genetic associations with platelet count and mean platelet volume, which in aggregate can explain large fractions of phenotypic variance, consistent with a complex genetic architecture and polygenic inheritance. Finally, we describe the large genetic diagnostic and discovery programmes, which, simultaneously to genome-wide association studies, have expanded the repertoire of genes and variants associated with extreme platelet phenotypes. These have advanced our understanding of the pathogenesis of hereditary macrothrombocytopenia and support a future clinical diagnostic strategy that utilises genotype alongside clinical and laboratory phenotype data.

Alinity hq platelet results are equivalent with the international reference method in thrombocytopenic samples

INTRODUCTION

Accurate and precise platelet (PLT) count is critical for the appropriate management of patients with thrombocytopenia. This study evaluated the performance of PLT counting with the Abbott Alinity hq hematology analyzer, which utilizes multi-dimensional optical technology.

METHODS

Imprecision, linearity, and accuracy were assessed per CLSI guidelines. Alinity hq PLT results were compared to the international flow cytometry reference method (IRM) in the concentration range of 6.3 to 103.0 × 10⁹ /L. Additional comparisons were made with Sysmex XN-3000 PLT counts: impedance (PLT-I), optical (PLT-O), and optical fluorescent (PLT-F) methods.

RESULTS

The average within-run %CV was 4.7% on patient samples with PLT concentrations ranging from 13.1 to 41.7 × 10⁹ /L, and the within-laboratory %CV was 3.6% at the level of 68.2 × 10⁹ /L. Linearity evaluation indicated a maximum deviation of 3.1% from the linear fit in the range of 0.1 to 316.8 × 10⁹ /L. Comparison between Alinity hq and the IRM PLT counts yielded a correlation coefficient of 0.99 and predicted bias of 0.0 and -0.5 × 10⁹ /L at 10.0 and 20.0 × 10⁹ /L transfusion thresholds, respectively. Alinity hq PLT counts also correlated well with Sysmex PLT counts, with strongest correlation obtained with PLT-F and PLT-O (r = .99) methods.

CONCLUSION

This study demonstrated excellent analytical performance of Alinity hq PLT counting in thrombocytopenic samples, equivalency with the IRM and strong agreement with Sysmex PLT-F and PLT-O methods. The Alinity hq multi-dimensional optical PLT count is available with every CBC without additional reagents and may help promote efficiency in clinical laboratories.

Pseudothrombocytopenia-A Review on Causes, Occurrence and Clinical Implications

Pseudothrombocytopenia (PTCP), a relative common finding in clinical laboratories, can lead to diagnostic errors, overtreatment, and further (even invasive) unnecessary testing. Clinical consequences with potential life-threatening events (e.g., unnecessary platelet transfusion, inappropriate treatment including splenectomy or corticosteroids) are still observed when PTCP is not readily detected. The phenomenon is even more complex when occurring with different anticoagulants. In this review we present a case of multi-anticoagulant PTCP, where we studied different parameters including temperature, amikacin supplementation, measurement methods, and type of anticoagulant. Prevalence, clinical risk factors, pre-analytical and analytical factors, along with clinical implications, will be discussed. The detection of an anticoagulant-dependent PTCP does not necessarily imply the presence of specific disorders. Conversely, the incidence of PTCP seems higher in patients receiving low molecular weight heparin, during hospitalization, or in men aged 50 years or older. New analytical technologies, such as fluorescence or optical platelet counting, will be soon overturning traditional algorithms and represent valuable diagnostic aids. A practical laboratory approach, based on current knowledge of PTCP, is finally proposed for overcoming spuriously low platelet counts.

Performance evaluation of platelet counting of Abbott Alinity hq and Sysmex XN-9000 automated hematology analyzer compared with international reference method

INTRODUCTION

Accurate platelet counting is essential for risk assessment of bleeding and thrombosis. Abbott Alinity hq hematology analyzer was recently introduced, and its performance in platelet counting has yet to be evaluated comprehensively. In this study, we evaluated the performance of the optical platelet counting of Abbott Alinity hq (Alinity-PLT) and the impedance and fluorescent platelet counting of Sysmex XN-9000 (XN-PLT-I and XN-PLT-F) compared with the international reference method.

METHODS

Blood samples were analyzed via Alinity hq and XN-9000 with PLT-F channel. Immuno-platelet (ImmnoPLT) reference method was performed with CD41/CD61 antibodies using FACSLyric^TM flow cytometer (BD). Precision was determined using 10 replicates in a single run, and the platelet counts of Alinity-PLT, XN-PLT-I, XN-PLT-F, and ImmnoPLT were compared.

RESULTS

At a platelet count of 13 × 10⁹ /L, the CVs of Alinity-PLT, XN-PLT-I, and XN-PLT-F were 4.2%, 6.7%, and 4.3%, respectively, and at a platelet count of 44 × 10⁹ /L, all showed a CV of less than 3%. For the total 210 samples, all three methods showed a very strong correlation with ImmunoPLT (r > 0.99). For platelet levels below 20 × 10⁹ /L, XN-PLT-F showed the strongest correlation with ImmunoPLT (r = 0.975), and for platelet levels of 20-100 × 10⁹ /L, Alinity-PLT and XN-PLT-I were comparable to ImmunoPLT. For platelet levels of 100-450 × 10⁹ /L, XN-PLT-I was the most comparable to ImmunoPLT, and for platelet levels above 450 × 10⁹ /L, Alinity-PLT was comparable to ImmunoPLT.

CONCLUSIONS

All three methods were highly correlated with ImmunoPLT, and each method had different performance advantages according to the platelet levels.

Platelet indices in patients with chronic inflammatory arthritis: a systematic review and meta-analysis

Correlation between platelet indices and chronic inflammatory arthritis (CIA) remains a moot point today. This meta-analysis aimed to evaluate whether platelet (PLT) count, mean platelet volume (MPV) and platelet distribution width (PDW) associated with rheumatoid arthritis (RA), ankylosing spondylitis (AS) and psoriatic arthritis (PsA). A systematic literature search was performed in PubMed, EMBASE, and Web of Science up to August 2019. Pooled standardized mean differences (SMD) and 95% confidence interval (CI) were calculated using a random-effect model. As a result, 34 studies were included, encompassing 17 on RA, 12 on AS, 3 on PsA and 2 on both RA and AS. In these studies, PLT count was significantly higher in RA (SMD = 0.55, 95% CI = 0.36-0.73, P < .001), AS (SMD = 0.53, 95% CI = 0.36-0.70, P < .001) and PsA patients (SMD = 1.29, 95% CI = 0.82-1.77, P < .001) than that in healthy subjects, while MPV and PDW presented nonsignificant differences in these intergroup comparisons (P > .05), and similar results were observed in subgroup analyses. The meta-regression analysis demonstrated that there were strong positive correlations between erythrocyte sedimentation rate and PLT count, and weak correlation trend between the disease activity score and PLT count in both RA and AS subjects without statistically significant difference. The sensitivity analysis indicated that these results were not unduly influenced by any single study. In conclusion, this meta-analysis demonstrated that PLT count was elevated in CIA patients and could be suitable for evaluating the disease activity, whereas MPV and PDW were independent of CIA.

Platelet Counting: Ugly Traps and Good Advice. Proposals from the French-Speaking Cellular Hematology Group (GFHC)

Despite the ongoing development of automated hematology analyzers to optimize complete blood count results, platelet count still suffers from pre-analytical or analytical pitfalls, including EDTA-induced pseudothrombocytopenia. Although most of these interferences are widely known, laboratory practices remain highly heterogeneous. In order to harmonize and standardize cellular hematology practices, the French-speaking Cellular Hematology Group (GFHC) wants to focus on interferences that could affect the platelet count and to detail the verification steps with minimal recommendations, taking into account the different technologies employed nowadays. The conclusions of the GFHC presented here met with a "strong professional agreement" and are explained with their rationale to define the course of actions, in case thrombocytopenia or thrombocytosis is detected. They are proposed as minimum recommendations to be used by each specialist in laboratory medicine who remains free to use more restrictive guidelines based on the patient’s condition.

Reticulated platelets – clinical application and future perspectives

Reticulated platelets are immature platelets freshly released from the bone marrow into the circulation and contain vestigial amounts of ribonucleic acid. Thus, they can serve as an indicator for the activity of thrombopoiesis. Despite the current lack of a standardized reference method, two types of hematology analyzers have incorporated a fully automated measurement of reticulated platelets. The “immature platelet fraction” (IPF; Sysmex XE-/XN-series) has some clinical utility in the differential diagnosis of thrombocytopenia. This is less clear for “reticulated platelets” (retPLT; Abbott CELL-DYN Sapphire/Alinity HQ). The usefulness of these parameters in the prediction of platelet recovery after chemotherapy or stem cell transplantation and as a decision aid for platelet transfusions has not been unequivocally confirmed. Recent findings have shown an association of reticulated platelets with an adverse risk in patients with coronary artery disease and stroke as well as resistance to anti-platelet therapy. Furthermore, a role of reticulated platelets for the prediction of sepsis was indicated. However, validation in larger prospective trials is necessary to establish the clinical benefit of reticulated platelets in these conditions. This review gives an overview of the available analytical methods and summarizes the current knowledge regarding the clinical application of reticulated platelets.

Multicenter performance evaluation of the Abbott Alinity hq hematology analyzer

Background

Alinity hq (Abbott) is a new high-throughput hematology analyzer that exclusively employs optical principles for detecting and enumerating blood cells. It reports 29 parameters, including a six-part white blood cell (WBC) differential. The aim of this multicenter study was to evaluate the analytical and clinical performance of the Alinity hq.

Methods

Complete blood count (CBC) results and morphological flagging were compared to that of CELL-DYN Sapphire (Abbott) and 2 × 200-cell manual differential results, on 1473 whole-blood samples from a well-defined patient population from three different clinical laboratories in the Netherlands. In addition, within-run and within-laboratory precision, linearity, limit of quantitation, carryover and sample stability were assessed. External quality assessment samples were also evaluated.

Results

Data analysis demonstrated strong concordance of Alinity hq results with those of CELL-DYN Sapphire for all CBC parameters, except for basophil granulocytes. Alinity hq WBC differential showed high level of agreement with manual differential results and exhibited a better agreement with manual basophil results than CELL-DYN Sapphire. The sensitivity of the Alinity hq Blast flag was 57.6%, equal to the 57.6% sensitivity of the CELL-DYN Sapphire’s Blast Alert. When considering samples with ≥5% blasts, the sensitivity of the Alinity hq Blast flag was 70.0%. Analytical performance of Alinity hq was shown to be consistent with state-of-the-art (SOTA) performance characteristics.

Conclusions

Alinity hq CBC measurands demonstrated good overall agreement with results obtained with CELL-DYN Sapphire, as well as manual WBC differential. The analytical and clinical performance characteristics of Alinity hq make it well suited for clinical laboratories.

Analytical performance of automated platelet counts and impact on platelet transfusion guidance in patients with acute leukemia

The aim of this study was to evaluate the performance of automated impedance platelet counts by Beckman Coulter LH780 (PLT-LH), Sysmex XN-3000 (PLT-XNi) and fluorescence method by Sysmex XN-3000 (PLT-F) in patients with acute leukemia. Blood specimens were subjected to platelet measurements by evaluated methods and then compared against the international reference method (IRM). Eighty-two blood specimens were included. Bland-Altman plots of the differences between the evaluated methods and IRM demonstrated mean biases of PLT-LH, PLT-XNi and PLT-F of 9 × 10⁹/L, 11 × 10⁹/L and 2 × 10⁹/L, respectively. For platelet transfusion guidance, all evaluated methods had acceptable accuracy. For platelet transfusion guidance, the sensitivities of PLT-LH, PLT-XNi and PLT-F were 33.3, 25.0 and 83.3%, respectively, at a transfusion threshold of 10 × 10⁹/L, and 73.1, 61.5 and 84.6%, respectively, at transfusion threshold of 20 × 10⁹/L. High blast count was associated with inaccurate PLT-LH and PLT-XNi. In conclusion, the PLT-F demonstrated excellent performance for diagnosis of thrombocytopenia and for platelet transfusion guidance in the evaluated specimens from acute leukemia patients. With respect to clinical relevance, careful blood smear review is necessary in case of high blast counts.