Sara Altinier

Cardiac troponin I, cardiac troponin T and creatine kinase MB concentrations in umbilical cord blood of healthy term neonates.

Aims: To measure and compare cardiac troponin I, cardiac troponin T and creatine kinase MB concentrations in the umbilical cord blood of healthy term infants and to investigate the relationship between maternal and neonatal troponin values at birth. Methods: Troponin I, troponin T and creatine kinase MB concentrations were measured from the umbilical cord samples of 85 healthy term neonates and in the blood samples of their respective mothers at birth. Results: Median (interquartile range) umbilical cord concentrations were 0 μg/L (0–0) for troponin I, 0 μg/L (0–0.019) for troponin T and 4.90 μg/L (3.90–6.61) for creatine kinase MB. Troponin I and T concentrations were higher than the detection limit for the assay in 2 (2.3%) and 41 (48.2%) neonates, respectively. Two mothers (2.3%) had cTnT levels above the detection limit; none of them had increased levels of cTnI.

Cardiac troponin I in asphyxiated neonates.

Background: Cardiac troponins T (cTnT) and I (cTnI) are well-established markers in detecting myocardial ischemic damage in adults. Perinatal asphyxia is associated with cardiac dysfunction. Objectives: To evaluate serum concentrations of cTnI in asphyxiated neonates and to investigate whether cTnI is correlated with the traditional markers of asphyxia. Methods: Blood samples were collected from 13 asphyxiated neonates (umbilical artery pH <7.18 and either a 1-min Apgar score <4 or a 5-min Apgar score <7) and 39 controls. Data on gestation, birth weight, sex, Apgar scores, mode of delivery, umbilical pH, creatinine, serum activity of aspartate and alanine aminotransferase, and QTc interval were investigated. Results: Median (range) cTnI concentrations were significantly higher in asphyxiated neonates with respect to healthy infants: 0.36 µg/l (0.05–11) versus 0.04 µg/l (0.04–0.06); p < 0.01. In asphyxiated babies, no statistically significant correlations were found between concentrations of cTnI and the other markers of asphyxia. Conclusions: In asphyxiated neonates, cTnI concentrations are higher with respect to healthy infants, suggesting the presence of myocardial damage in this group of high-risk patients. cTnI does not correlate with the traditional markers of asphyxia.

High serum cardiac troponin T concentrations in preterm infants with respiratory distress syndrome

In preterm infants with respiratory distress syndrome (RDS), cardiac function is negatively influenced by the severity of the lung disease. On day 2 of life, cardiac troponin T (cTnT), biochemical marker of myocardial injury, was measured in 46 preterm infants (gestational age ≤32 wk), 26 with RDS and 20 without: median (range) 0.38 (0.02–1.57) μgL vs 0.13 (0.02–0.85) μgL, respectively.

Point-of-care testing of cardiac markers: results from an experience in an Emergency Department.

AIM An experimental approach to the use of point-of-care testing for cardiac markers in the Emergency Department (ED) of our Institution has been carried out using two devices (SCS, Dade Behring and Triage Cardiac Panel, Biosite Diagnostics) for the measurement of cardiac markers. RESULTS (1) From the analytical point of view, a fundamental tool for an efficient management of patients was the agreement between results from point-of-care testing and from the instruments located in STAT lab and/or central laboratory: in about 5% of patients, a lack of comparability of data, resulted in an inappropriate admission of patients (medical vs. intensive care unit). (2) The actual total turnaround time (TAT) in the management of samples sent to STAT lab was estimated to be equal to 82.5 min (50th percentile). (3) In the same organizational setting, the use of a point-of-care device produced a turnaround time equal to 17 min (50th percentile). (4) The reduction in turnaround time resulted in a faster discharge for five patients who had normal ECG findings and cardiac marker values, the Delta time (POCT-STAT lab) ranging from -10 to -70 min. CONCLUSIONS The point-of-care option evaluated also in relation to personnel issues for staff working in the ED, brought some interesting questions about the characteristics of POCT devices (easy to use 100%, safety for operator 91%) and the obtained results (quantitative and correlated to STAT lab, 91%), as well as the need of other options such as the implementation of rapid tube sample delivery.

Heterophilic antibody interference in a non-endogenous molecule assay: an apparent elevation in the tacrolimus concentration.

BACKGROUND In drug monitoring assays the most common interferences are due to hematocrit, other drugs or their metabolites, while the interference by heterophilic antibodies has been reported only when measuring endogenous molecules. In the present paper a heterophilic antibody interference in the tacrolimus measurement is described. METHODS Samples from a patient treated with tacrolimus were analyzed on RxL Dimension analyzer. Ranging drug concentrations from 49 to 12.5 microg/L, even after the interruption of the treatment, confirmation analysis were performed using heterophilic blocking tubes before tacrolimus measurement on the same analyzer, then testing the samples on V-Twin System, finally incubating the samples with chlorophenol red beta-d-galactopyranoside, beta-galactosidase, polyclonal mouse IgG, protein A and Protein G resin. RESULTS The elevated tacrolimus concentrations were due to the presence of an interference attributable to heterophilic antibodies, as confirmed by treating the samples with heterophilic blocking tubes and protein G resin. CONCLUSIONS a) The interference caused by heterophilic antibodies can be found not only in immunoassays measuring endogenous molecules, but also in those for exogenous molecules; b) the pre-treatment sample procedure, which represent the main difference between the methods affected and unaffected by the interference, is a fundamental step in removing the antibodies responsible of the interference.

High-Sensitivity C-Reactive Protein in Umbilical Cord of Small-for-Gestational-Age Neonates

Background: Several epidemiological studies reported a significant correlation between low birth weight and cardiovascular disease in adult life. Recent studies showed that an inflammatory response has been associated with the development of atherosclerosis. High-sensitivity C-reactive protein (hs-CRP) has been demonstrated to be a sensitive marker of this inflammatory process giving prognostic information in apparently healthy general population as well as in patients with symptomatic atherosclerosis.We hypothesized that the chronic inflammatory process, involved in the future atherosclerotic injury, could be found during the fetal period. Objectives:To compare umbilical cord hs-CRP concentrations between small-for-gestational-age (SGA) and appropriate-for-gestational age (AGA) neonates. Methods: Concentrations of hs-CRP (Dade Boehring®) were measured in 35 SGA infants (gestational age: mean ± SD, 34.6 ± 3.0 weeks) and in 69 AGA neonates (34.2 ± 3.4 weeks). Neonates with a history of suspected or proven feto-maternal infection were excluded. Results: In SGA infants, hs-CRP concentrations were significantly higher than in AGA neonates: median (range); 0.06 mg/l (0.02–5.53) vs. 0.02 mg/l (0.02–0.55); p = 0.003. Concentrations of hs-CRP were higher than the detection limit (0.04 mg/l) in 25 (71.5%) SGA infants and in 28 (40.6%) AGA neonates (p = 0.002). Conclusions: In SGA infants, hs-CRP concentrations are higher than in AGA neonates suggesting the presence of an inflammatory process in this group of patients during the fetal life. This finding could be involved in the previously reported relationship between low birth weight and cardiovascular disease in adult life.

Multicenter evaluation of hemoglobin A1c assay on capillary electrophoresis.

BACKGROUND Hemoglobin A1c (HbA1c) measurement is currently used for the routine monitoring of long-term glycemic status, thus playing a fundamental role in the management of this disease. Since this marker has recently been recommended as an additional tool for diagnosing diabetes, its of the utmost importance to ensure that the precision and accuracy of HbA1c methods are satisfactory. METHODS We assessed the analytical performances of the Capillarys 2 Flex Piercing® analyzer and compared the results obtained with those from two other widely used HPLC instruments. Furthermore, we evaluated the convenience and ergonomics of the system in authentic routine work conditions in three centers. RESULTS Within-laboratory (n=40) and between-laboratory (n=120) imprecision CV% using four blood samples with different concentrations of HbA1c were <3.4% and <3.1% using IFCC units and <2.1% and <2.0% using NGSP units, respectively. The obtained trueness (<3 mmol/mol, <0.3%) was highly satisfactory, nor was HbA1c measurement compromised by the presence of the commonly present hemoglobinopathies. The comparison made with established methods revealed excellent agreement (r>0.985). CONCLUSIONS The evaluated method is precise, accurate and robust, with a high throughput. It also allows the identification of the most frequent Hb variants and therefore may be a valid alternative to other methods currently proposed for routine use in clinical laboratories.

Effect of patent ductus arteriosus and indomethacin treatment on serum cardiac troponin T levels in preterm infants with respiratory distress syndrome

Abstract Cardiac troponin T (cTnT) represents a sensitive and specific marker of ischemic myocardial damage in adult and neonatal populations. The aim of this study was to detect the potential ischemic effect of persistent patent ductus arteriosus (PDA) and indomethacin treatment on the coronary vascular bed by measuring cTnT concentrations. cTnT levels were measured in 23 preterm infants (<32 weeks of gestational age) with respiratory distress syndrome (RDS), 11 with PDA and 12 without, at 2, 4, and 7 days after birth. cTnT concentrations (mean ± SEM) significantly decreased (P < 0.05) from the 2nd (0.63 ± 0.09 μg/l) and the 4th (0.77 ± 0.13 μg/l) to the 7th postnatal day (0.28 ± 0.04 μg/l). At day 2 after birth, cTnT levels in preterm infants with RDS were significantly higher (P < 0.05) than our reference values for healthy preterm neonates (0.63 ± 0.09 μg/l vs 0.18 ± 0.04 μg/l). No differences were found between RDS infants with and without PDA at 2 (0.65 ± 0.13 vs 0.61 ± 0.14 μg/l), 4 (0.71 ± 0.21 vs 0.87 ± 0.16 μg/l), and 7 (0.26 ± 0.05 vs 0.29 ± 0.07 μg/l) days of life. In infants with PDA, cTnT levels did not differ before the first dose of indomethacin was given (0.65 ± 0.14 μg/l) or 2 h (0.65 ± 0.15 μg/l) and 48 h (0.71 ± 0.21 μg/l) afterwards. Conclusion In preterm infants with RDS the occurrence of PDA and indomethacin treatment are not associated with ischemic cardiac damage as detected by cTnT measurements.

Analytical and clinical evaluation of a new heart-type fatty acid-binding protein automated assay

Abstract Background: The accurate and rapid recognition of myocardial injury in patients presenting in the emergency department (ED) with chest pain continues to be a clinical challenge. Heart-type fatty acid-binding protein (H-FABP) appears to be one of the best candidates among the new early cardiac markers studied. Methods: We evaluated the analytical characteristics of a new quantitative and fully automated H-FABP assay (Randox Laboratories Ltd., Crumlin, UK) and compared its clinical performance with respect to the myoglobin (Myo) assay (Dade Behring, Milan, Italy). A precision study was carried out by testing three levels of quality control (QC) material and two in-house pool (P) samples. To test the accuracy of H-FABP determinations in plasma (lithium-heparin) samples, H-FABP concentrations measured in a set of matched sera and plasma samples were compared. A total of 77 non-consecutive patients (51 males and 26 females; 62±16years) who presented to the ED with chest pain suggesting myocardial ischemia were enrolled. The patients were classified into two groups (acute myocardial infarction, n=22; non-acute myocardial infarction, n=55) on the basis of the discharge diagnosis. Results: The between-day imprecision for three levels of control material and serum pool samples was 6.26%–8.04% (range 2.32–44.03μg/L) and 9.03%–12.63% (range 11.85–65.13μg/L), respectively. In the serum vs. plasma study, bias was +0.178 (95% CI −0.033 to +0.389). The best cut-off and the associated diagnostic efficacy were 95μg/L and 89.47% for Myo and 5.09μg/L and 98.70% for H-FABP, respectively. Conclusions: H-FABP determination in patients with ischemic symptoms may be a more reliable early indication of cardiac damage than myoglobin. Clin Chem Lab Med 2006;44:1383–5.

Serum free light chain reference values: a critical approach.

OBJECTIVES The clinical usefulness of serum free light chain (FLC) measurement in the management of patients with plasma cell proliferative disorders has been reported in several papers, and most clinical studies use the reference ranges declared by the manufacturer. The aim of the present study was to evaluate the reproducibility of FLCs immunoassay and to validate the reference range, before introducing it in routine setting. DESIGN AND METHODS Internal quality control materials and a pool of fresh serum samples were used to evaluate imprecision; 162 fresh sera from healthy blood donors were analyzed to evaluate the reference range for FLCs. In order to verify the κ/λ FLC ratio, 43 sera from patients with polyclonal hypergammaglobulinemia were tested. The FLC immunoassay was performed using a nephelometer with the Freelite reagents. RESULTS The imprecision studies performed using a serum pool tested with two different lots of reagents showed a mean CV of 16.09% for κFLC and of 16.72% for λFLC. Lower CV%s and different mean values were found by calculating the results from each specific lot separately, while different results were obtained using the control materials provided by the manufacturer. In reference subjects, the 2.5-97.5th percentiles were found to be 4.52-22.33 and 4.84-21.88mg/L for κFLC and λFLC, respectively. The range for κ/λ ratio (0.65-2.36) was validated with the values obtained from subjects with polyclonal hypergammaglobulinemia. In retesting 15 samples from blood donor subjects with a different lot of reagents, mean bias percentages of 17.60 for κFLC and 15.26 for λFLC were obtained. CONCLUSIONS These findings confirm the lot-to-lot variability of the FLC assays also in the measurement of polyclonal light chains, as well as the need to carefully validate the reference values.