Determination of reference ranges for immature platelet and reticulocyte fractions and reticulocyte hemoglobin equivalent

Immature platelets in COVID-19

Platelets play a critical role in immune response. Coronavirus disease 2019 (COVID-19) patients with a severe course often show pathological coagulation parameters including thrombocytopenia, and at the same time the proportion of immature platelets increases. In this study, the platelet count and the immature platelet fraction (IPF) of hospitalized patients with different oxygenation requirements was investigated daily over a course of 40 days. In addition, the platelet function of COVID-19 patients was analyzed. It was found that the number of platelets in patients with the most severe course (intubation and extracorporeal membrane oxygenation (ECMO)) was significantly lower (111.5 ∙ 10⁶ /mL) than in the other groups (mild (no intubation, no ECMO): 203.5 ∙ 10⁶ /mL, p < .0001, moderate (intubation, no ECMO): 208.0 ∙ 10⁶ /mL, p < .0001). IPF tended to be elevated (10.9%). Platelet function was reduced. Differentiation by outcome revealed that the deceased patients had a highly significant lower platelet count and higher IPF (97.3 ∙ 10⁶ /mL, p < .0001, 12.2%, p = .0003).

Donor sex, pre-donation hemoglobin, and manufacturing affect CD71+ cells in red cell concentrates

BACKGROUND

Circulating CD71⁺ red blood cells (RBCs) have been reported to play an immunomodulatory role in vivo, which may contribute to adverse donor-recipient sex-mismatched transfusion outcomes. However, it is not clear how CD71⁺ RBC quantity in red cell concentrates (RCCs) is affected by manufacturing methods and donor factors such as donor sex, donor age, pre-donation hemoglobin (Hb), venous Hb (Hb_v ) levels, and donation frequency.

METHODS

We determined CD71⁺ RBCs and Hb levels in whole blood (WB) from healthy donors (42 male/38 female). Using small-scale red cell filtration (RCF) and whole blood filtration (WBF) methods, leukoreduced RCCs were processed from WB samples (n = 6) and the CD71⁺ RBCs were determined at days 1, 7, and 28. We examined uni- and multivariate associations among CD71⁺ RBCs, donor factors, and manufacturing method.

RESULTS

Male donors had a higher CD71⁺ RBC concentration than females (p < .001), especially male donors aged 17-50 years with 1 or 2 WB donations over the previous 12 months. Donors with a Hb_v above 155 g/L had a higher CD71⁺ RBC concentration than an Hb_v level below 140 g/L (p < .05). There was a positive correlation between pre-donation Hb and CD71⁺ RBC concentration (Pearson r = 0.41). WBF RCCs had a higher total number of CD71⁺ RBCs than RCF-produced RCCs on day 1 (p < .05).

DISCUSSION

RCCs have variable numbers of CD71⁺ RBCs. This makes understanding the impact of donor factors and manufacturing methods on the immunomodulatory effect of CD71⁺ RBCs critical in exploring donor-recipient sex-mismatched transfusions.

Evaluation of RET-He values as an early indicator of iron deficiency anemia in pregnant women

INTRODUCTION

During pregnancy, women are at an increased risk of developing iron-deficiency anemia.

OBJECTIVE

The objective of this study was to assess the diagnostic performance of the reticulocyte hemoglobin equivalent (RET-He) in the early detection of iron-deficiency anemia in a group of pregnant women and to establish a reference range for this parameter in a group of control individuals.

METHOD

A total of 60 patients and 130 control subjects were included in the study. Blood samples collected from the subjects were submitted to a complete blood count and a serum ferritin test and the data were analyzed by comparing the groups and ROC curves.

RESULTS

The reference range found for the RET-He was between 29.75pg and 38.24pg, with a median of 35pg. The receiver operating characteristic (ROC) curve analysis for the ferritin parameter showed an area under the curve of 0.732 for the RET-He, 0.586 for hemoglobin, 0.551 for the mean corpuscular hemoglobin concentration and 0.482 for the mean corpuscular volume.

CONCLUSION

Early diagnosis of iron deficiency anemia in pregnancy is essential to prevent damage to both maternal and fetal health. The RET-He presents an excellent potential as an auxiliary tool for the diagnosis of iron deficiency in pregnant women.

Reference intervals for reticulocyte parameters (reticulocyte haemoglobin equivalent and immature reticulocyte fraction) in first-trimester pregnancy

Reticulocyte parameters including reticulocyte haemoglobin equivalent (Ret-He) and immature reticulocyte fraction (IRF) are newly recognised hematological parameters that are being used for diagnosis and follow-up of anaemic patients. Reference intervals of these parameters have been established in different populations, however, the data relating to pregnancy are still lacking. One hundred and fifty-five first-trimester pregnant females were screened and the reference interval was calculated after selecting the patient with fixed criteria. R statistical software was used for statistical calculations. We tried to establish a reference interval of Ret-He content and IRF in first-trimester pregnancy in our study.IMPACT STATEMENTWhat is already known on this subject? Ret-He and IRF have been established as the marker of iron deficiency and iron-deficiency anaemia in different age groups and as a marker of response to iron therapy. However, literature is scarce regarding the reference intervals of these parameters, especially in pregnancy.What do the results of this study add? This study establishes the reference interval of newer reticulocyte parameters in first-trimester pregnancy which is not yet established in the literature. Establishing a reference interval is required for any laboratory parameters to be used in the clinical context.What are the implications of these findings for clinical practice and further research? The results of this study may help in making a clinical decision regarding iron deficiency in early pregnancy which is one of the common clinical problems in pregnancy. This study also serves as a baseline study for further studies of reference intervals for newer reticulocyte parameters in pregnancy. A similar study with a larger study population and follow-up with iron therapy may establish these parameters as one of the important markers of iron deficiency in pregnancy and help institute iron therapy on case-to-case basis.

Reticulated Platelets-Which Functions Have Been Established by In Vivo and In Vitro Data?

Reticulated platelets (RP) are the youngest platelet fraction released into the circulation. These immature platelets have increased RNA content, a larger cell volume, more dense granules, higher levels of surface activation markers and are thought to be more reactive compared to their mature counterparts. RP have been associated with cardiovascular disease, diabetes and increased mortality. Yet only a few animal studies investigating RP have been conducted so far and further investigations are warranted. Established methods to count RP are flow cytometry (staining with thiazole orange or SYTO13) or fully automated hematology analyzers (immature platelet fraction, IPF). IPF has been established as a diagnostic parameter in thrombocytopenia, cardiovascular disease and, in particular, the response to antiplatelet therapy. This review seeks to provide an overview of the key features of RP as well as preanalytical and analytical aspects that need to be considered when working with this platelet population.

αIIbβ3 variants in ten families with autosomal dominant macrothrombocytopenia: Expanding the mutational and clinical spectrum

Background

Rare pathogenic variants in either the ITGA2B or ITGB3 genes have been linked to autosomal dominant macrothrombocytopenia associated with abnormal platelet production and function, deserving the designation of Glanzmann Thrombasthenia-Like Syndrome (GTLS) or ITGA2B/ITGB3-related thrombocytopenia.

Objectives

To describe a series of patients with familial macrothrombocytopenia and decreased expression of αIIbβ3 integrin due to defects in the ITGA2B or ITGB3 genes.

Methods

We reviewed the clinical and laboratory records of 10 Portuguese families with GTLS (33 patients and 11 unaffected relatives), including the functional and genetic defects.

Results

Patients had absent to moderate bleeding, macrothrombocytopenia, low αIIbβ3 expression, impaired platelet aggregation/ATP release to physiological agonists and low expression of activation-induced binding sites on αIIbβ3 (PAC-1) and receptor-induced binding sites on its ligand (bound fibrinogen), upon stimulation with TRAP-6 and ADP. Evidence for constitutive αIIbβ3 activation, occurred in 2 out of 9 patients from 8 families studied, but also in 2 out of 12 healthy controls. We identified 7 missense variants: 3 in ITGA2B (5 families), and 4 in ITGB3 (5 families). Three variants (αIIb: p.Arg1026Trp and p.Arg1026Gln and β3: p.Asp749His) were previously reported. The remaining (αIIb: p.Gly1007Val and β3: p.Thr746Pro, p.His748Pro and p.Arg760Cys) are new, expanding the αIIbβ3 defects associated with GTLS. The integration of the clinical and laboratory data allowed the identification of two GTLS subgroups, with distinct disease severity.

Conclusions

Previously reported ITGA2B and ITGB3 variants related to thrombocytopenia were clustered in a confined region of the membrane-proximal cytoplasmic domains, the inner membrane clasp. For the first time, variants are reported at the outer membrane clasp, at the transmembrane domain of αIIb, and at the membrane distal cytoplasmic domains of β3. This is the largest single-center series of inherited macrothrombocytopenia associated with αIIbβ3 variants published to date.

Immature platelets: a review of the available evidence

Immature platelets or reticulated platelets are newly released thrombocytes. They can be identified by their large size and high RNA cytoplasm concentration. Immature platelet fraction (IPF) represents the percentage of immature circulative platelets to the total number of platelets. The development of analytical standardization of this hematological parameter by new automated devices allowed a better exploration of its contribution in a context of thrombocytopenia. In fact, several studies had confirmed its clinical utility to differentiate immune thrombocytopenia from other causes of thrombocytopenia. IPF can also predict platelets recovery after chemotherapy and successful engraftment. In addition, immature platelets have shown utility in other diseases such as coronary artery diseases, bacterial infections and liver diseases. Despite all these advantages, immature platelet fraction can be increased in some cases of thrombocytopenia characterized by platelets hypoproduction. The aim of this review is to present the immature platelet fraction contribution in clinical practice.

Historical control data for hematology parameters obtained from toxicity studies performed on different Wistar rat strains: Acceptable value ranges, definition of severity degrees, and vehicle effects

The physiological and health status of control animals may vary. Due to this variation, it is important to define acceptable ranges of control hematology parameters to gain a better understanding of adverse and non-adverse effects of test substances. After generating historical control data for two Wistar rat strains (RccHan™:WIST and Crl:WI(Han)) from different breeders, the data sets were statistically analyzed using Minitab®. After noticing that single outliers can affect the study control data set, the respective outliers were verified relative to the available histopathology findings, for example, inflammatory pulmonary lesions following vehicle aspiration or spontaneous sperm granuloma affecting the health status and hematology data of the respective animals. Such data points were excluded from the control data set. Comparing both data sets, it was obvious that different blood sampling and anesthesia methods as well as strain differences may result in slightly different values. After excluding the outliers, a data set from animals with presumably good health status was generated to define acceptable ranges and severity degrees. To evaluate effects, possibly influencing hematology parameters and defined acceptable ranges, selected vehicles and different study types were observed.

Infected RBC flag/parameter provided by Mindray BC-6800 haematology analyzer aid the diagnosis of malaria

Background

The Mindray BC-6800 haematology analyzer (BC-6800) provides a dedicated flag ‘Infected RBC’ (InR) and the number of InR (InR#)/the permillage of InR (InR‰) in routine blood testing as a screening tool for malaria in endemic areas. This study sought to evaluate the effectiveness of the BC-6800 flag parameter for aiding the diagnosis of malaria.

Methods

A total of 181 samples were tested using the Mindray BC-6800 haematology analyzer, including 117 malaria-infected samples collected from Yunnan, China, and 64 samples from healthy controls. Microscopy examination was conducted as reference when stained thick blood film revealed the presence of malaria parasites identified as Plasmodium vivax and Plasmodium falciparum. The receiver operating characteristic (ROC) curve analysis was developed using Analyse-it v4.92.3. The Kappa value was determined to evaluate the agreement between BC-6800 and light microscopy.

Results

The sensitivity of InR‰ generated by BC-6800 for P. vivax and P. falciparum was 88.3 and 24.1%, respectively; specificity of InR‰ for malaria parasites was 84.3 and 84.3%, respectively; positive predictive value and negative predictive value was 89.4 and 82.7% for P. vivax, and 52.8 and 60.3% for P. falciparum. There was a strong correlation between ΔWBC and InR‰ (R² = 0.9731 for P. vivax and R² = 0.9757 for P. falciparum). There was also a significant correlation between parasitaemia and InR# in P. vivax-infected samples (R² = 0.734). InR# was evaluated using ROC curve analysis, the area under the ROC curve is 0.95 with a 95% confidence interval of 0.926 to 0.974, and the cut-off value is 0.01 × 10⁹/L for P. vivax. However, the ring stage and the early trophozoite stage of Plasmodium cannot be detected easily on BC-6800, possibly because of the small size and low nucleic acid content of these stages.

Conclusions

The findings suggest that the flag ‘InR’ and the parameters ‘InR#/InR‰’ provided by the BC-6800 haematology analyzer could be used to screen for malaria in a clinical setting.

Reference intervals for absolute and percentage immature platelet fraction using the Sysmex XN-10 automated haematology analyser in a UK population

BACKGROUND

Immature platelet fraction (IPF) estimation is a non-invasive and sensitive test that is available on recently introduced Sysmex XN-series of automated haematology analysers. It is a direct cellular indicator of thrombopoiesis. The aim of this study was to establish reference intervals for IPF, for both absolute (A-IPF) and percentage (%-IPF) measurements.

MATERIAL AND METHODS

A total of 2366 samples that met the inclusion criteria were assayed for full blood count on the Sysmex XN-10 and a non-parametric percentile method was used for calculating the reference intervals.

RESULTS

After the outliers were excluded, the reference interval for %-IPF and A-IPF on Sysmex XN-10 were 1.6-10.1% and 4.37-23.21 × 10⁹/L in total individuals, respectively. There was a statistical significance noted between the sexes (p = .004) for %-IPF, therefore a sex-specific reference interval was established, which was 1.8-10.0% for the males and 1.5-10.1% for females. No significant difference in sex status for A-IPF and age status for both %-IPF and A-IPF was observed. A very poor correlation was estimated between age versus %-IPF, ρ = 0.0156, and age versus A-IPF, ρ = -0.0023, indicating that there is no overall biological relationship between age and these parameters. As expected, a strong correlation between %-IPF and A-IPF was noted which could be attributed to their inter-relatedness.

CONCLUSIONS

This large-scale study showed comparable reference intervals with the previous studies for %-IPF and A-IPF in a UK population. It found the need to establish sex-specific reference intervals for %-IPF, but not for A-IPF, whereas reference intervals were found to be stable across the age range.