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Before adopting a new hematology analyzer in clinical laboratories, evaluating its platelet counting performance is critical. To assess the analytical performance of impedance (PLT-I), hybrid (PLT-H), and optical (PLT-O) platelet counts on the novel Mindray BC-7800 (BC-7800) and to compare platelet parameters obtained from the BC-7800 and Sysmex XN-3000 (XN-3000), including PLT-I, PLT-O, and PLT-F (optical fluorescent platelet count using oxazine dye), against the international reference method (IRM) in specimens with platelet interferences. Analytical parameters of the BC-7800, including limit of blank, linearity, reproducibility, and carryover, were evaluated. Interference testing included 126 specimens with red blood cell (RBC) microcytosis and 21 specimens from patients with blasts. Diagnostic performance against the IRM was assessed at platelet transfusion thresholds of 10 × 103/µL and 20 × 103/µL. The BC-7800 met acceptable criteria for most basic parameters, except within-run precision for PLT-I and PLT-H in some thrombocytopenic specimens. In RBC microcytosis, all methods showed strong correlations with the IRM, though PLT-I exhibited proportional bias. In leukemia specimens, PLT-O from the BC-7800 and PLT-F from the XN-3000 showed the strongest agreement with the IRM, while PLT-H and PLT-O from the XN-3000 exhibited systematic bias. Specificity and positive predictive value were excellent across all methods. Sensitivity, negative predictive value, and accuracy were highest for PLT-O from the BC-7800 and PLT-F. The BC-7800 demonstrated reliable platelet analysis, particularly with PLT-O in thrombocytopenic and interference-prone specimens. PLT-H and optical fluorescent platelet methods showed strong reliability in specimens with RBC microcytosis, while PLT-O from the BC-7800 and PLT-F offered the highest accuracy for guiding platelet transfusion decisions.

Background This study investigated the accuracy of the “PLT Clumps?” flag triggered by different channels on the Sysmex XN haematology analyser in identifying two sample states and to optimize the platelet review strategy for cancer patients. Methods 570 samples flagged “PLT Clumps?” in CBC + DIFF mode were analysed. After excluding clots, retesting was conducted in CBC + DIFF + PLT‐F mode. The accuracy of the “PLT Clumps?” flag and its correlation with PLT aggregation (PA) or fibrin precipitation (FP) were evaluated. Low‐platelet count samples were collected for a second blood draw to confirm whether pseudothrombocytopenia (PTCP) was present. The incidence and positive predictive value (PPV) of the “PLT Clumps?” flag across different tumours were also analysed. Results Among 85 verified cases (PA = 17, FP = 63), the overall PPV of the “PLT Clumps?” flag was 14.9% (85/570) in CBC + DIFF mode, 3.5% in WNR channel only, 73.9% in WDF channel only, and 94.4% in dual‐channel. In CBC + DIFF + PLT‐F mode, the overall PPV and NPV were 98.5% (65/66) and 97.0% (484/499), respectively. PA and FP accounted for 73.9% (17/23) and 26.1% (6/23) of the PLT‐F‐only flagged samples, respectively, and all WDF‐only and dual‐flagged cases were triggered by FP. The incidence of PTCP in samples flagged for “PLT Clumps?” in CBC + DIFF + PLT‐F mode was 80%. Samples from patients with hepatobiliary tumours showed highest flagging rate (20.4%) but a lower PPV. Conclusion The correlation between “PLT Clumps?” flags originating from different channels and two common preanalytical factors interfering in PLT counting was analysed, and the platelet review strategy for cancer patients was optimized.

Although several studies demonstrated that platelet count is higher in women, decreases with age, and is influenced by genetic background, most clinical laboratories still use the reference interval 150-400×10(9) platelets/L for all subjects. The present study was to identify age- and sex-specific reference intervals for platelet count. We analysed electronic records of subjects enrolled in three population-based studies that investigated inhabitants of seven Italian areas including six geographic isolates. After exclusion of patients with malignancies, liver diseases, or inherited thrombocytopenias, which could affect platelet count, reference intervals were estimated from 40,987 subjects with the non parametric method computing the 2.5° and 97.5° percentiles. Platelet count was similar in men and women until the age of 14, but subsequently women had steadily more platelets than men. The number of platelets decreases quickly in childhood, stabilizes in adulthood, and further decreases in oldness. The final result of this phenomenon is that platelet count in old age was reduced by 35% in men and by 25% in women compared with early infancy. Based on these findings, we estimated reference intervals for platelet count ×10(9)/L in children (176-452), adult men (141-362), adult women (156-405), old men (122-350) and, old women (140-379). Moreover, we calculated an \"extended\" reference interval that takes into account the differences in platelet count observed in different geographic areas. The age-, sex-, and origin-related variability of platelet count is very wide, and the patient-adapted reference intervals we propose change the thresholds for diagnosing both thrombocytopenia and thrombocytosis in Italy.

In a collaboration between the Canadian Laboratory Initiative on Pediatric Reference Intervals (CALIPER) and the Canadian Health Measures Survey (CHMS), we determined reference value distributions using an a priori approach and created a comprehensive database of age- and sex-stratified reference intervals for clinically relevant hematologic parameters in a large household population of children and adults. The CHMS collected data and blood samples from 11 999 respondents aged 3-79 years. Hematology markers were measured with either the Beckman Coulter HmX or Siemens Sysmex CA-500 Series analyzers. After applying exclusion criteria and removing outliers, we determined statistically relevant age and sex partitions and calculated reference intervals, including 90% CIs, according to CSLI C28-A3 guidelines. Hematology marker values showed dynamic changes from childhood into adulthood as well as between sexes, necessitating distinct partitions throughout life. Most age partitions were necessary during childhood, reflecting the hematologic changes that occur during growth and development. Hemoglobin, red blood cell count, hematocrit, and indices (mean corpuscular volume, mean corpuscular hemoglobin, and mean corpuscular hemoglobin concentration) increased with age, but females had lower hemoglobin and hematocrit starting at puberty. Platelet count gradually decreased with age and required multiple sex partitions during adolescence and adulthood. White blood cell count remained relatively constant over life, whereas fibrinogen increased slightly, requiring distinct age and sex partitions. The robust dataset generated in this study has allowed observation of dynamic biological profiles of several hematology markers and the establishment of comprehensive age- and sex-specific reference intervals that may contribute to accurate monitoring of pediatric, adult, and geriatric patients.

There are racial, ethnic and geographical differences in complete blood count (CBC) reference intervals (RIs) and therefore it is necessary to establish RIs that are population specific. Several studies have been carried out in Africa to derive CBC RIs but many were not conducted with the rigor recommended for RI studies hence limiting the adoption and generalizability of the results. By use of a Beckman Coulter ACT 5 DIFF CP analyser, we measured CBC parameters in samples collected from 528 healthy black African volunteers in a largely urban population. The latent abnormal values exclusion (LAVE) method was used for secondary exclusion of individuals who may have had sub-clinical diseases. The RIs were derived by both parametric and non-parametric methods with and without LAVE for comparative purposes. Haemoglobin (Hb) levels were lower while platelet counts were higher in females across the 4 age stratifications. The lower limits for Hb and red blood cell parameters significantly increased after applying the LAVE method which eliminated individuals with latent anemia and inflammation. We adopted RIs by parametric method because 90% confidence intervals of the RI limits were invariably narrower than those by the non-parametric method. The male and female RIs for Hb after applying the LAVE method were 14.5-18.7 g/dL and 12.0-16.5 g/dL respectively while the platelet count RIs were 133-356 and 152-443 x10(3) per μL respectively. Consistent with other studies from Sub-Saharan Africa, Hb and neutrophil counts were lower than Caucasian values. Our finding of higher Hb and lower eosinophil counts compared to other studies conducted in rural Kenya most likely reflects the strict recruitment criteria and healthier reference population after secondary exclusion of individuals with possible sub-clinical diseases.

The aim of this study is to evaluate the performance of different platelet counting methods (optical, impedance, fluorescence and hand counting) applied in different analysers by comparing with the international flow cytometric reference method (IRM). A total of 333 blood samples from different subgroups (168 cases with thrombocytopenia, 136 cases with normal platelet counts and 29 cases with thrombocytosis) were tested. Regarding IRM as the gold standard, we compared the accuracy and precision of different platelet count methods; i.e. LH780 (impedance), BC-6000 Plus (optical (O) and impedance (I)), Sysmex XN-9000 (optical (O), impedance (I), fluorescence (F)), and hand counting. Sysmex XN-9000-F (r = 0.988) had the best correlation with IRM for thrombocytopenic samples; BC-6000 Plus-I (r = 0.966) was more relevant to IRM than any other method for samples with normal platelet counts. Correlation between Sysmex XN-9000-I (r = 0.960) and IRM was the highest among these methods for samples with thrombocytosis. For bias evaluation, the average bias of Sysmex XN-9000-F was -1.5 × 109/L (95% LA = -9.4 to +6.4) for samples with thrombocytopenia, compared with IRM. BC-6000 Plus-I had a small mean difference with IRM for samples with normal platelet counts or thrombocytosis. Moreover, all evaluated methods had acceptable sensitivity, specificity, and concordance rates as compared with IRM in the diagnosis of thrombocytopenia and thrombocytosis. Platelet counting by Sysmex XN-9000-F is more accurate than other methods for thrombocytopenic samples. BC-6000 Plus-I has superior association and consistency for normal platelet counts. As for thrombocytosis patients, Sysmex XN-9000-I has the highest correlation with IRM while Sysmex XN-9000-O has the highest diagnosis efficacy.

Prison-based HCV treatment rates remain low due to multiple barriers, including accessing transient elastography for cirrhosis determination. The AST-to-platelet ratio index (APRI) and FIB-4 scores have excellent negative predictive value (NPV) in hospital cohorts to exclude cirrhosis. We investigated their performance in a large cohort of prisoners with HCV infection. This was a retrospective cohort study of participants assessed by a prison-based hepatitis program. The sensitivity, specificity, NPV and positive predictive value (PPV) of APRI and FIB-4 for cirrhosis were then analysed, with transient elastography as the reference standard. The utility of age thresholds as a trigger for transient elastography was also explored. Data from 1007 prisoners were included. The median age was 41, 89% were male, and 12% had cirrhosis. An APRI cut-off of 1.0 and FIB-4 cut-off of 1.45 had NPVs for cirrhosis of 96.1% and 96.6%, respectively, and if used to triage prisoners for transient elastography, could reduce the need for this investigation by 71%. The PPVs of APRI and FIB-4 for cirrhosis at these cut-offs were low. Age ≤35 years alone had a NPV for cirrhosis of 96.5%. In those >35 years, the APRI cut-off of 1.0 alone had a high NPV >95%. APRI and FIB-4 scores can reliably exclude cirrhosis in prisoners and reduce requirement for transient elastography. This finding will simplify the cascade of care for prisoners living with hepatitis C.

The aim was to elude differences in published paediatric reference intervals (RIs) and the implementations hereof in terms of classification of samples. Predicaments associated with transferring RIs published elsewhere are addressed. A local paediatric (aged 0 days to < 18 years) population of platelet count, haemoglobin level and white blood cell count, based on first draw samples from general practitioners was established. PubMed was used to identify studies with transferable RIs. The classification of local samples by the individual RIs was evaluated. Transference was done in accordance with the Clinical and Laboratory Standards Institute EP28-A3C guideline. Validation of transference was done using a quality demand based on biological variance. Twelve studies with a combined 28 RIs were transferred onto the local population, which was derived from 20,597 children. Studies varied considerably in methodology and results. In terms of classification, up to 63% of the samples would change classification from normal to diseased, depending on which RI was applied. When validating the transferred RIs, one RI was implementable in the local population. Conclusion: Published paediatric RIs are heterogeneous, making assessment of transferability problematic and resulting in marked differences in classification of paediatric samples, thereby potentially affecting diagnosis and treatment of children.What is Known:• Reference intervals (RIs) are fundamental for the interpretation of paediatric samples and thus correct diagnosis and treatment of the individual child.• Guidelines for the establishment of adult RIs exist, but there are no specific recommendations for establishing paediatric RIs, which is problematic, and laboratories often implement RIs published elsewhere as a consequence.What is New:• Paediatric RIs published in peer-reviewed scientific journals differ considerably in methodology applied for the establishment of the RI.• The RIs show marked divergence in the classification of local samples from healthy children.

A knowledge of the limitations of automated platelet counting is essential for the effective care of thrombocytopenic patients and management of platelet stocks for transfusion. For this study, 29 external quality assessment specimen pools with platelet counts between 5 and 64 × 10(9)/L were distributed to more than 1,100 users of 23 different hematology analyzer models. The same specimen pools were analyzed by the international reference method (IRM) for platelet counting at 3 reference centers. The IRM values were on average lower than the all-methods median values returned by the automated analyzers. The majority (~67%) of the automated analyzer results overestimated the platelet count compared with the IRM, with significant differences in 16.5% of cases. Performance differed between analyzer models. The observed differences may depend in part on the nature of the survey material and analyzer technology, but the findings have implications for the interpretation of platelet counts at levels of clinical decision making.

Aims To derive reference values for red cell variables and platelet counts from a cohort of infants sampled at precise ages during the first 13 months of life. Methods Blood counts, reticulocyte counts and zinc protoporphyrin concentrations were obtained from healthy term infants of North European ancestry at 2, 5 and 13 months of age. Results Mean cell volume (MCV) and mean cell haemoglobin (MCH) values did not differ significantly between 5 and 13 months and MCH concentration was unaffected by age. Values of all other variables at any one age differed significantly from those at the other two. Haemoglobin, mean cell haemoglobin, zinc protoporphyrin and platelet values (95% ranges) at 2 (n=119), 5 (n=97) and 13 months (n=42) were, respectively, 91–125, 101–129 and 105–133 g/L; 28.6–33.1, 24.5–28.7 and 24.3–28.7 pg; 36–116, 25–91 and 27–57 micromol/mol haem; and 216–658, 241–591 and 209–455×109/L. At 2 and 5 months, respectively, 26.9% and 10.8% of subjects had platelet counts >500×109/L. Reticulocyte counts at 2 months and MCV and MCH values at 5 months were significantly higher in girls. In boys, red cell distribution width values were significantly higher at 5 months, and zinc protoporphyrin values at both 2 and 5 months. Conclusions These findings indicate the value of obtaining reference data at precise ages during infancy and confirm and extend earlier reports indicating a gender difference in laboratory measures used to assess iron status in early infancy.