International normalized ratio testing with point-of-care coagulometer in healthy term neonates

Reliability of International Normalized Ratio Results in the CoaguChek Pro II System in a Clinical Setting

The National Institute of Cardiology has previously used the CoaguChek® XS Plus system (Roche Diagnostics International Ltd), comparing capillary blood prothrombin time/international normalized ratio (PT/INR) results with those obtained using BCS-XP/Thromborel (Siemens). We assessed the reliability of PT/INR results using the third-generation CoaguChek Pro II system, the CoaguChek XS Plus system, and cobas® t 411 for citrated plasma analysis. Venous and capillary PT/INR were measured (N = 204). Spearman's correlation, Bland-Altman, and concordance analysis between methods were conducted. Spearman's correlation coefficients between venous/capillary INR were high for CoaguChek Pro II versus CoaguChek XS Plus (r = 0.994), CoaguChek Pro II versus cobas t 411 (r = 0.967), and CoaguChek XS Plus versus cobas t 411 (r = 0.968). Good concordance was observed among capillary methods (concordance coefficient [κ] = 0.888) and remaining relationships (P < .001 for all): cobas t 411 versus CoaguChek XS Plus (κ = 0.696) and cobas t 411 versus CoaguChek Pro II (κ = 0.684). In conclusion, good agreement was observed between CoaguChek Pro II, CoaguChek XS Plus, and cobas t 411.

Developmental Hemostasis: The Evolution of our Coagulation System

Developmental hemostasis describes the evolution of the coagulation system from the neonatal period through adulthood. Neonates have lower levels of coagulation factors and elevated screening levels at birth. These levels can be influenced by various circumstances including gestational age, labor effects, and clinical status. The most commonly used screening tests for coagulopathy are the prothrombin time, partial thromboplastin time, and fibrinogen level. These values can be difficult to interpret as every laboratory has its own age-specific reference ranges. An understanding of developmental hemostasis is important when evaluating, diagnosing, and treating clinical manifestations, including vitamin K deficiency, surgical needs, infections, inherited thrombophilias, and inherited bleeding disorders. The mainstay of treatment for bleeding or hemorrhage is platelet and fresh frozen plasma transfusions. For the treatment of thrombosis, unfractionated heparin and low-molecular-weight heparin are the 2 most commonly used anticoagulants in the neonatal setting.

Capillary blood reference intervals for platelet parameters in healthy full-term neonates in China

Background

No consensus has been reached on capillary blood reference intervals for platelet parameters in full-term neonates. We aimed to establish neonatal capillary blood reference intervals for platelet parameters and evaluate influences of sex, gestational age and postnatal age on platelet parameters.

Methods

This study was a prospective investigation and implemented in 594 healthy full-term neonates from 12 to 84 h of age, using SYSMEX XN-9000 haematology automatic analyser by means of capillary blood. Reference intervals for platelet parameters were defined by an interval of 2.5th − 97.5th percentiles.

Results

Capillary reference interval for platelet count was (152–464) × 10⁹/L. No significance was found between sex-divided reference intervals for platelet parameters. The values of platelet count changed minimally across gestational age (37–41 weeks) and postnatal age (12–84 h). Reference intervals for other platelet parameters were affected by these factors to a different extent.

Conclusions

We established capillary blood reference intervals for platelet parameters in the first days after birth of full-term neonates in China.

From Hemophilia to Deep Venous Thrombosis Patient Samples: How to Perform an Easy Coagulometer Validation Process According to Available Guidelines

Validation protocols for the evaluation of coagulometers are needed to help professionals select the most suitable system for their regular laboratory routines. The objective of this study was to show how high standard protocols for the coagulometer validation process can fit into the daily laboratory routine. For this study, 45 healthy individuals and 112 patient samples were analyzed. From the patient samples, 51 were investigated for deep venous thrombosis, 27 for coagulopathy, 19 for antivitamin K therapy, and 15 for hemophilia. For the assessment, the performance of the 3 coagulometers and 1 point-of-care device was considered. One of the coagulometers was a new acquisition evaluated for precision, linearity, throughput, and carryover in the first moment, and the new coagulometer was then compared with the other well-established equipment in the laboratory. In normal plasma, coefficient of variation was ≤1.8% for total precision in screening tests and ≤3.5% for within-run precision in specific assays. For prothrombin time/international normalized ratio, no significant difference was found when comparing methods. Our study showed how to compare the capacity of a reagent in order to discriminate patients with severe hemophilia from patients with moderated hemophilia, and the κ coefficient agreement was 0.669 (95% confidence interval: 0.3-1.0; P < .001). d-dimer evaluated in patients with deep venous thrombosis and controls showed a 20% discrepancy between the methods. In our experience across Latin America, the number of laboratories that has performed this process is limited. In this study, we demonstrated how to adapt the validation process for the hemostasis laboratory routine to help the professional chose the best and more suitable option.

Validation of a Portable Coagulometer for Routine In-Hospital Use for Newborns

OBJECTIVES

To verify the reliability and clinical benefits of the coagulation tests made by a point of care device in newborn admitted to a neonatal unit.

DESIGN

We made a statistical comparison between results obtained by the point of care device versus conventional laboratory analysis.

SETTING

Level 3 neonatal unit.

PATIENTS

Thirty-one infants admitted to the neonatal unit at the San Cecilio University Hospital (Granada, Spain) were recruited to this study.

INTERVENTIONS

All underwent a double analytical determination: a small drop of blood was taken for analysis with a portable coagulometer (qLabs Electrometer Plus) and the rest of the blood sample was analyzed with conventional hospital laboratory equipment.

MEASUREMENTS AND MAIN RESULTS

According to the linearity test performed, the measuring methods presented a good linear regression fit. Lin's concordance coefficient showed a "good" agreement for activated partial prothrombin time and international normalized ratio (>0.61) and a moderate one for prothrombin time (0.41-0.6) for the sample of newborns.

CONCLUSIONS

The portable coagulometer qLabs Electrometer Plus device has the potential to be an alternative to standard hospital coagulation autoanalyzers in a subset of patients where the amount of blood drawn can have significant risks. Our study is the first of its kind to analyze the use of this device with severely ill newborns.

Seasonal variation in the international normalized ratio of neonates and its relationship with ambient temperature

Background

The morbidity and mortality rates due to cardiovascular events such as myocardial infarction are known to exhibit seasonal variations. Moreover, changes in the ambient temperature are reportedly associated with an increase in these events, which may potentially involve blood coagulation markers. Bleeding due to vitamin K deficiency in neonates, which is associated with high mortality and a high frequency of neurological sequelae, is more commonly observed during the summer season and in warm regions in Japan. To determine the presence of seasonal variation and the influence of ambient temperature on blood coagulation markers in healthy term neonates, we assessed the international normalized ratio (INR) values measured using CoaguChek XS.

Methods

We studied 488 consecutive healthy term neonates who were born at a perinatal center between July 2012 and June 2013. The INR values were measured using CoaguChek XS in 4-day-old neonates who received nursing care in the newborn nursery throughout the duration of hospitalization. The seasonal variations in the INR values and environmental effects on the INR were assessed.

Results

The mean monthly INR values peaked in July (1.13 ± 0.08), whereas the lowest values were observed in January (1.05 ± 0.08). Higher levels of INR were observed during the summer season (June to August) than during the winter season (December to February). Simple linear regression analysis indicated the presence of weakly positive but significant correlations between INR and outdoor temperature (r = 0.25, p < 0.001), outdoor relative humidity (r = 0.19, p < 0.001), and room relative humidity (r = 0.24, p < 0.001), and the presence of a significant negative correlation between INR and room temperature (r = −0.13, p = 0.02). Furthermore, multiple linear regression analysis showed that only outdoor temperature significantly influenced the INR.

Conclusions

A seasonal variation in the INR values was observed among neonates, possibly due to the variation in ambient temperature. Even though the neonates received nursing care in the newborn nursery that was constantly air-conditioned, the outdoor temperature was the most influential factor on INR.