Hyperferritinemia among very-low-birthweight infants in Thailand: a prospective cohort study.

OBJECTIVES: To determine the incidence of hyperferritinemia in VLBW infants, and its association with neonatal morbidity. STUDY DESIGN: Prospective cohort study in a tertiary-level hospital in Bangkok, from March 2022 to January 2023. Serum ferritin (SF) was measured in VLBW infants at one month and repeated monthly for those with hyperferritinemia (SF > 300 ng/mL). RESULTS: Gestational age and birth weight were 29.7 ± 2.4 weeks (mean ± SD) and 1100 g (IQR, 830, 1340). Hyperferritinemia was identified in 30.1% (95% CI, 20.8-41.4). After adjustment, only packed red cell transfusion >15 mL/kg was associated with hyperferritinemia (RR 3.1; 95% CI, 1.5-6.4). All elevated SF levels returned to normal within four months. Hyperferritinemia was associated with severe bronchopulmonary dysplasia (RR 2.3, 95% CI, 1.0-5.4) and retinopathy of prematurity (RR 3.5, 95% CI, 1.4-8.6). CONCLUSION: Hyperferritinemia is common among our VLBW infants, particularly after transfusion, and is associated with severe BPD and ROP.

Determination of Platelet Estimate Factor of Sysmex DI-60 Digital Morphology Analyzer for Platelet Count Estimation.

CONTEXT.­: In the Sysmex DI-60 digital morphology system, a platelet estimate factor (PEF) is used to calculate the estimated platelet count (PLT). OBJECTIVE.­: To determine the most accurate PEF by analyzing various specimens, including those with abnormal flag alerts, using both impedance (PLT-I) and optical fluorescent (PLT-F) PLT methods. A validation study was then conducted using random specimens to evaluate the accuracy of the PEF. DESIGN.­: This study included 120 blood specimens without flag alerts, and 120 blood specimens with flag alerts related to platelet abnormalities to determine the PEF. Each group was equally divided into thrombocytopenia, normal count, and thrombocytosis specimens. The PEF values obtained from the PLT-I and PLT-F methods were analyzed. An additional 120 specimens were used to compare the estimated PLT from PEF with the PLT-F count. Unadjusted PEF disregarded platelet ranges and flag alerts, whereas adjusted PEF incorporated them. RESULTS.­: The mean PEF values ranged within 9.95 to 12.99 for PLT-I-obtained values (PEF-I) and within 10.32 to 11.69 for PLT-F-obtained values (PEF-F) across different PLT ranges. The mean PEF values were significantly higher in specimens with flags compared with those without flags. The values were 12.43 compared with 10.19 for PEF-I and 11.45 compared with 10.4 for PEF-F. A significant difference was found between PEF-I and PEF-F in flagged specimens, with respective values of 12.43 and 11.45. There was excellent agreement between estimated PLTs using adjusted PEF and PLT-F. However, proportional biases were observed between estimated PLT using unadjusted PEF and PLT-F. CONCLUSIONS.­: Adjustment of PEF values according to specific platelet ranges and flag alert presence was shown to enhance the accuracy of PLT estimation using the Sysmex DI-60 system.

Reagent Effects on the Activated Partial Thromboplastin Time Clot Waveform Analysis: A Multi-Centre Study.

(1) Background: The activated partial thromboplastin time (APTT)- based clot waveform analysis (CWA) quantitatively extends information obtained from the APTT waveform through its derivatives. However, pre-analytical variables including reagent effects on the CWA parameters are poorly understood and must be standardized as a potential diagnostic assay. (2) Methods: CWA was first analysed with patient samples to understand reagent lot variation in three common APTT reagents: Pathromtin SL, Actin FS, and Actin FSL. A total of 1055 healthy volunteers were also recruited from seven institutions across the Asia-Pacific region and CWA data were collected with the Sysmex CS analysers. (3) Results: CWA parameters varied less than 10% between lots and the linear mixed model analysis showed few site-specific effects within the same reagent group. However, the CWA parameters were significantly different amongst all reagent groups and thus reagent-specific 95% reference intervals could be calculated using the nonparametric method. Post-hoc analysis showed some degree of influence by age and gender with weak correlation to the CWA (r < 0.3). (4) Conclusions: Reagent type significantly affects APTT-based CWA with minimal inter-laboratory variations with the same coagulometer series that allow for data pooling across laboratories with more evidence required for age- and gender-partitioning.

Kanamycin Supplement for the Disaggregation of Platelet Clumps in EDTA-Dependent Pseudothrombocytopenia Specimens.

OBJECTIVE: To indicate the ability to disaggregate platelet clumps by vortex mixing and kanamycin supplementation in EDTA-dependent pseudothrombocytopenia (EDTA-PTCP) specimens. MATERIALS AND METHODS: For patients with EDTA-PTCP, citrate-anticoagulated, primary EDTA-anticoagulated, vortex-mixed, and kanamycin-treated specimens were tested for complete blood count and platelet-related parameters. RESULTS: Forty-eight specimens were included. Nineteen (39.6%) of the vortex-mixed specimens and 42 (87.5%) of the kanamycin-treated specimens revealed platelet counts more than those of the primary EDTA specimens, with levels exceeding 100 × 109/L. The platelet count and platelet recovery of the kanamycin-treated specimens were higher than those of the vortex-mixed specimens. CONCLUSION: Kanamycin supplementation to EDTA-PTCP blood may be considered as an alternative approach when the recollection of specimens is impractical. Only platelet-related parameters from kanamycin treatment were suitable for guiding patient management. Further studies about the impact of these methods in patients with various conditions, such as in patients with advanced kidney disease, should be conducted.

Inappropriate use of D-dimer and impact on the test characteristics for deep vein thrombosis exclusion.

This study aimed to investigate the prevalence of the inappropriate use of D-dimer testing for deep vein thrombosis (DVT) exclusion, and to evaluate the diagnostic value of D-dimer testing compared between testing in appropriate and inappropriate conditions. A retrospective chart review of patients with D-dimer requests at Siriraj Hospital, Bangkok, Thailand during January-September 2017 was performed. Data relating to D-dimer requests, Wells score, imaging investigations, and coexisting conditions that cause elevated D-dimer without correlation to DVT were analyzed. From 2196 cases, there were 300 D-dimer requests for DVT diagnosis. Of those, 5 (1.7%) and 158 (53.6%) requests were considered to be absolutely inappropriate D-dimer test requests due to the absence of pre-test Wells score evaluation and testing in DVT-likely patients, respectively. One-hundred and forty-eight (49.3%) requests were considered to be the relatively inappropriate D-dimer test requests due to testing in patients with coexisting conditions that included malignancies, sepsis, surgery, trauma, arterial thrombosis, and pregnancy. Three patients had more than one of these conditions. Comparatively higher negative predictive values (NPVs) of D-dimer assay for DVT exclusion were observed when used in DVT-unlikely (100% versus 80%), and in patients without coexisting conditions (100% versus 66.7%). The present study revealed the rate of inappropriate D-dimer testing for DVT exclusion to be high and this may lead to missed DVT diagnosis, overuse of imaging study, and unnecessary cost of D-dimer testing. Appropriate patient selection before test request can improve the NPV of D-dimer for DVT exclusion.

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.

Performance Evaluation of High Fluorescence Lymphocyte Count: Comparability to Atypical Lymphocyte Count and Clinical Significance.

OBJECTIVES: To investigate the association between high-fluorescence lymphocyte cell (HFLC) and atypical lymphocyte (AL) counts, and to determine the clinical significance of HFLC. METHODS: We compared automated HFLC and microscopic AL counts and analyzed the findings. Patient clinical data for each specimen were reviewed. RESULTS: A total of 320 blood specimens were included. The correlation between HFLC and microscopic AL counts was 0.865 and 0.893 for absolute and percentage counts, respectively. Sensitivity, specificity, and accuracy of HFLC at the cutoff value of 0.1 × 109 per L for detection of AL were 0.8, 0.77, and 0.8, respectively. Studied patients were classified into 4 groups: infection, immunological disorders, malignant neoplasms, and others. Patients with infections had the highest HFLC. Most of those patients (67.7%) had dengue infection. CONCLUSION: HFLC counts were well-correlated with AL counts with the acceptable test characteristics. Applying HFLC flagging may alert laboratory staff to be aware of ALs.

Performance Evaluation of Automated Impedance and Optical Fluorescence Platelet Counts Compared With International Reference Method in Patients With Thalassemia.

CONTEXT: - Spurious platelet counts from automated methods have been reported in patients with abnormal red blood cells. However, there is no specific study regarding performance of platelet counts by automated methods in patients with thalassemia. OBJECTIVE: - To investigate the performance of automated platelet counts, including impedance (PLT-I) and optical fluorescent (PLT-O and PLT-F) methods, and compare them with the international reference method (IRM) for platelet counting in patients with thalassemia. DESIGN: - Two hundred forty-nine thalassemia specimens from various subtypes were examined. PLT-I, PLT-O, and PLT-F from a Sysmex XN analyzer were evaluated and compared against the IRM. Demographic data, platelet counts, and red blood cell parameters are shown. Comparability between evaluated methods and IRM, as well as test characteristics, is presented. Factors involving inaccurate PLT-I were analyzed. RESULTS: - Specimens with platelet counts ranging from 31 × 103/µL to 932 × 103/µL were included. Most patients were patients with thalassemia major. Correlation between PLT-I and IRM was lower than that of the other methods in overall patients. PLT-O and PLT-F were correlated to IRM when classifying patients according to clinically significant platelet ranges. All automated methods had acceptable sensitivities; however, specificity of PLT-I was low for diagnosis of thrombocytopenia. High RDW-CV (red blood cell distribution width-coefficient of variation) was an independent factor of inaccurate PLT-I measurement. CONCLUSIONS: - Among the evaluated methods, PLT-I was the method least correlated to IRM, with PLT-O and PLT-F comparable to IRM in patients with thalassemia. Optical platelet counts and careful blood smear examination are recommended alternative platelet counting methods, depending on the clinical setting.

Prevalence of 60 kda and 52 kda Ro/SS-A autoantibodies in anti-Ro positive Thai sera in Siriraj Hospital.

BACKGROUND: Anti-Ro antibody may directly react against either Ro60 or Ro52 or both antigens. To be more applicable for routine laboratory practice, the specific antigen type for antibody detection should be identified before test application. OBJECTIVE: Investigate the prevalence of 60 kDa and 52 kDa Ro/SS-A antibodies in Thai patients' sera in Siriraj Hospital. MATERIAL AND METHOD: Specimens for anti-Ro were requested between June and December 2005. They were tested with EUROLINE test kit for prevalence determination. The principle of the test is a qualitative in-vitro-assay that contains test strips coated with parallel lines of 14 highly purified antigens. Of 84 specimens requested for anti-Ro antibody, 76 were collected and tested with the EUROLINE test kits and eight were excluded due to inadequacy. RESULTS: The prevalence of anti-Ro60 and anti-Ro52 of all sera tested for anti-Ro by EUROLINE test kit were 30% (95% CI: 20-40%) and 26% (95% CI: 16-36%), respectively; and, those in anti-Ro positive Thai sera were 82% (95% CI: 68-96%) and 71% (95% CI: 54-88%), respectively. The prevalence of anti-Ro52 alone in anti-Ro positive Thai sera and all specimens requested for anti-Ro was about 18% (95% CI: 4-32%) and 7% (95% CI: 1-13%), respectively. The agreement and Kappa value between the two methods were 0.9 and 0.77, respectively. The study suggests that the test for anti-Ro detection should provide both Ro 60 and Ro 52 antigens. CONCLUSION: The prevalence of both anti-Ro 60 and anti-Ro 52 were quite common, therefore, the test for this specific antibody should provide both antigens for antibody detection.