Mariella Dipalo

Troponin I measured with a high sensitivity immunoassay is significantly increased after a half marathon run.

Abstract Only a few studies have assessed the kinetics of cardiac troponins after endurance exercise by using the novel high-sensitive (HS) immunoassays. These were based on the measurement of HS-TroponinT (TnT), but not HS-Troponin I (TnI), and exclusively involved marathon or ultra-marathon contests. TnI was measured in 17 healthy trained Caucasian males performing a 21 km, half-marathon, with the conventional AccuTnI and the HS-AccuTnI immunoassays. The concentration of HS-AccuTnI significantly increased from the mean baseline value of 2.9 ng/L (Interquartile range [IQR], 2.4– 4.3 ng/L) to 4.8 (IQR, 3.0–5.7 ng/L) after the run (p = 0.002), 9.0 ng/L (IQR, 5.8–15.3 ng/L) at 3h (p < 0.001), 12.3 ng/L (IQR, 7.1–21.5 ng/L) at 6h (p < 0.001), and 4.5 ng/L (IQR, 2.8–6.0 ng/L) at 24 h (p = 0.003) afterwards. The variation throughout the study period was statistically significant (p < 0.001). Age, training history, finishing time and exercise intensity were not associated with changes of HS-AccuTnI. The values of the TnI measured with the conventional AccuTnI immunoassay were always below the 99th percentile reference limit, except in one subject 3 h after the run, and in two subjects 6 h after the run. These results attest that TnI values measured with the novel HS-AccuTnI immunoassay were significantly increased in athletes participating in a half marathon.

Influence of hemolysis on troponin testing: studies on Beckman Coulter UniCel Dxl 800 Accu-TnI and overview of the literature

Abstract Background: Hemolyzed specimens are the leading pre-analytical problem in the laboratory practice, and exert a negative impact on test results. We assessed the reliability of Beckman Coulter UniCel Dxl 800 Accu-TnI testing on hemolyzed specimens. Methods: Twelve non-hemolyzed K2EDTA-anticoagulated samples displaying Accu-TnI values >0.20 μg/L and nine with values <0.04 μg/L were selected and three aliquots were obtained from each. The first (“#A”) was processed without further manipulation, whereas the second (“#B”) and third (“#C”) were hemolyzed by aspirating anticoagulated blood through a thin needle. Plasma was separated and tested for hemolysis index (HI) and Accu-TnI. Results: As compared with aliquot #A (HI: 0), a progressive increase of hemolysis occurred in aliquots #B (HI: 25) and #C (HI: 45). The concentration of Accu-TnI gradually decreased from aliquots #A (0.89 μg/L, 0.20–20.16 μg/L), to aliquots #B (0.81 μg/L, 95% CI 0.17–18.37 μg/L; p=0.041) and #C (0.78 μg/L, 95% CI 0.15–17.48 μg/L; p=0.026). In 0/12 (aliquots #B) and 3/12 cases (aliquots #C) the percent decrease exceeded 20% variation. The values remained unchanged in nine samples with Accu-TnI <0.04 μg/L. Conclusions: Accu-TnI values decrease in hemolyzed samples, but the bias might not be clinically significant in samples with hemoglobin <14.5 g/L.

Analytical evaluation of Diazyme procalcitonin (PCT) latex-enhanced immunoturbidimetric assay on Beckman Coulter AU5800.

Abstract Background: This study was aimed to evaluate the analytical performance of the novel Diazyme procalcitonin (PCT) immunoturbidimetric assay on Beckman Coulter AU5800. Methods: Diazyme PCT is a latex-enhanced immunoturbidimetric assay, developed for use on laboratory instrumentations with capability of reading absorbance at 600 nm. This analytical evaluation included the assessment of limit of blank (LOB), limit of detection (LOD), functional sensitivity, imprecision, linearity, carryover, and method comparison between Diazyme PCT and Kryptor PCT on 129 routine serum inpatient samples. Results: The LOB, LOD, and functional sensitivity of Diazyme PCT were 0.16, 0.26, and 0.28 ng/mL, respectively. The intra- and inter-assay imprecision of Diazyme PCT was between 2.9% and 7.8%. The linearity was excellent in the range of PCT values between 0.16 and 56 ng/mL, and the carryover was negligible (0.02%). A highly significant agreement was found between Kryptor PCT and Diazyme PCT in a range of concentrations between 0.16 and 111 ng/mL (Diazyme PCT=1.10×Kryptor PCT–0.89; r=0.960; p<0.001). The mean bias was 0.48 ng/mL (95% CI, –0.58 to 1.54 ng/mL). The strength of agreement between Kryptor PCT and Diazyme PCT was between 85% and 96% at 0.50, 2.0, and 10 ng/mL cutoffs. Conclusions: Diazyme PCT appears to be a reliable assay for diagnosis and management of critical care patients susceptible to severe bacterial infections.

Hemoconcentration induced by exercise: Revisiting the Dill and Costill equation.

The Dill and Costill equation is used to estimate the exercise‐induced hemoconcentration. However, this calculation requires drawing an extra whole‐blood sample, which cannot be frozen and has to be analyzed with dedicate instrumentation in a relative short time. The aim of the present study was to explore the usefulness of some serum biochemical parameters to estimate hemoconcentration induced by exhaustive exercise. Fourteen healthy male subjects (19–34 years) performed a15‐min running test at 110% of anaerobic threshold speed. Hemoglobin, hematocrit, brain natriuretic peptide (BNP), creatinine, gamma‐glutamyltransferase (GGT), total‐proteins, albumin, total calcium (Ca), K+, Na+, and Cl− were determined in blood samples taken before, after exercise, and after a 30‐min recovery period. Plasma volume loss (ΔPV) was calculated by Dill and Costill equation. At post‐exercise and after recovery, the percentage increments of total‐proteins, albumin, GGT and Ca correlated significantly with ΔPV. Bland–Altman analyses showed that correcting BNP, creatinine, and K+ concentration by Ca percentage increments yield biases and limits of agreement that are acceptable when compared with Dill and Costill equation correction. Ca concentration may be used as a hemoconcentration biomarker in high‐intensity exercise, which would allow scientists and physicians avoid extra costs, facilitate in‐field research, and delayed estimation of hemoconcentration using stored serum samples.

Evaluation of the analytical performances of the novel Beckman Coulter AU5800.

OBJECTIVES To assess the analytical performance of Beckman Coulter AU5800. DESIGN AND METHODS Imprecision, linearity and comparison studies were performed on 12 routine clinical chemistry tests. RESULTS Imprecision was comprised between 0.4 and 3.0%. The linearity was excellent, with regression coefficients always >1.000. The correlation with analogous tests on Unicell DxC ranged from 0.894 and 1.000. The productivity was 4884 tests/h. CONCLUSIONS We found optimal balance between performance and productivity for the AU5800.

Multicenter comparison of automated procalcitonin immunoassays

Objectives A multicenter study to compare results of BRAHMS Kryptor PCT with those obtained using four BRAHMS-partnered procalcitonin (PCT) automated immunoassays (DiaSorin Liaison, BioMérieux Vidas, Roche Cobas E601 and Siemens Advia Centaur) and the Diazyme immunotubidimetric assay implemented on four clinical chemistry platforms (Abbott Architect c16000, Siemens Advia 2400, Roche Cobas C501 and Beckman Coulter AU5800). Design and methods One hundred serum samples from in-patients with PCT values between 0.10 and 58.7 ng/mL were divided into aliquots and tested with the nine different reagents and analyzers. BRAHMS PCT Kryptor results were used as reference. Results Compared to BRAHMS PCT Kryptor, significant differences in results were observed on Vidas, Advia Centaur, Architect, Cobas C501 and AU5800. However, the correlation coeffiecients (r) with BRAHMS PCT Kryptor were between 0.899 and 0.988. The mean bias was less than ±1.02 ng/mL, except for Vidas (2.70 ng/mL). The agreement at three clinically relevant cut-offs was optimal: between 83–98% at 0.50 ng/mL, 90–97% at 2.0 ng/mL, and 98% at 10 ng/mL. The comparison of Diazyme PCT across the four clinical chemistry analyzers yielded high correlation coefficients (r between 0.952 and 0.976), a mean bias less than ±0.9 ng/mL, acceptable agreement at 0.5 ng/mL (>82%), and high concordance at the 2.0 ng/mL (>97%) and 10 ng/mL (>98%) cut-offs. Conclusions The methods and applications evaluated in this multicenter study are aligned with BRAHMS PCT Kryptor and can be used for predicting the risk of progression to systemic inflammation in patients with bacterial infections using the conventional PCT diagnostic thresholds.

The concentration of highly-sensitive troponin I is increased in patients with brain injury after mild head trauma

Although some studies have previously highlighted that myocardial injury may frequently occur in patients with head trauma [1–3], none of them has specifically measured cardiospecific troponins using the novel highly-sensitive (HS) immunoassays, nor the study population has included patients with mild head trauma, i.e., with a Glasgow Coma Score (GCS) ≥14. This prospective investigationwas based on all consecutive patients aged 14 to 80 years, presenting at the emergency department (ED) of the Academic Hospital of Parma (Italy) between September and November 2012 with a history of mild head trauma and GCS comprised between 14 and 15 at presentation. Patients fulfilled the local criteria for mild head trauma requiring CT scanning, due to coexistence of predetermined risk factors. Blood samples were collected within 3 h after head trauma, and serum HS troponin I (HS-TnI) was assessed with the prototype Beckman Coulter HS-AccuTnI on Access 2 (Beckman Coulter Inc., Chaska, Minnesota, USA). The limit of detection and the 99th percentile upper reference limit (URL) of this assay are 2.1 ng/L and 8.6 ng/L, respectively [4]. Unenhanced computer tomography (CT) scanning was performed with 16-slice Siemens Somatom Emotion (Siemens AG, Henkestr, Germany) within 30 to 60 min from ED admission. Positive CT was established in the presence of intracranial lesions, including acute subdural, epidural or parenchymal hematoma, traumatic subarachnoid haemorrhage, cerebral contusion and brain swelling. Significance of differences and frequency distribution of HS-TnI values was assessed with Kruskal–Wallis (for continuous variables) and chi-squared tests (for categorical variables), respectively. Results of measurements were finally reported as median and interquartile range (IQR). Statistical analysis was performed with Analyse-it for Microsoft Excel (Analyse-it Software Ltd., Leeds, UK). The studywascarriedout in accordancewith theDeclaration ofHelsinki, under the terms of all relevant local legislation. The final study population consisted in 42 patients (median age 51 years, IQR 32–72 years; 14 females and 28 males), 8 of whom (19%) with positive CT. No significant difference was found for age (p=0.150) and gender (p=0.172) distributions between CT positive and negative groups. As shown in Fig. 1, the median concentration of HS-TnI was more than 2-fold higher in patients with positive CT (10.3 ng/L; IQR 3.0–20.9 ng/L) than in thosewith negative CT (4.6 ng/ L; IQR 2.7–7.9 ng/L; p=0.003). The frequency of HS-TnI values above the 99th percentile URL was also significantly higher in patients with positive CT than in those with negative CT (i.e., 63 versus 21%; pb0.001). The occurrence of ECG abnormalities in patients with severe brain injury, namely subarachnoid haemorrhage, has been well documented andhas beenattributed to the onsetof reversible neurogenicmyocardial dysfunction secondary to a variety of potential mechanisms including massive catecholamine discharge, tachycardia, hypertension and coronary vasospasm [2,3]. Although a concomitant increase of troponin values measured with conventional or contemporary immunoassays has also been reported in these patients [1,3], no previous study has investigated the concentration of HS-troponin(s) in subjects presenting at the ED with mild head trauma. Increased values of cardiospecific troponins, especiallywhenmeasuredwith novel HS-immunoassays, are the cornerstone for diagnosing both reversible and irreversible myocardial injury [5,6]. Therefore, the results of our prospective investigation provide the first evidence that patients with brain injury after moderate head trauma have a high likelihood of developing myocardial involvement, as mirrored by the remarkable increased frequency ofHS-TnI values above the 99th percentile URL, and should be thereby triaged and monitored accordingly. The authors of this manuscript have certified that they comply with the Principles of Ethical Publishing in the International Journal of Cardiology.

Analytical Evaluation of Free Testosterone and Cortisol Immunoassays in Saliva as a Reliable Alternative to Serum in Sports Medicine

This study was aimed to investigate whether measurement of free testosterone and cortisol in saliva is a reliable alternative to their assessment in serum for monitoring physical fitness in professional athletes.

Analytical assessment of the Beckman Coulter Unicel DxI AccuTnI + 3 immunoassay

*Corresponding author: Prof. Giuseppe Lippi, Laboratory of Clinical Chemistry and Hematology, U.O. Diagnostica Ematochimica, Azienda Ospedaliero-Universitaria di Parma, Via Gramsci, 14, 43126 – Parma, Italy, Phone: +0039-0521-703050, +0039-0521-703791, E-mail: glippi@ao.pr.it, ulippi@tin.it Mariella Dipalo, Paola Avanzini and Rosalia Aloe: Laboratory of Clinical Chemistry and Hematology, Academic Hospital of Parma, Parma, Italy Alessandro Formentini: Service of Transfusion Medicine and Immunohematology, Academic Hospital of Parma, Parma, Italy

Multicenter Comparison of Seven 25Oh Vitamin D Automated Immunoassays / Multicentrično Poređenje Sedam Automatizovanih Imunoeseja Za 25Oh Vitamin D

Summary Background: The measurement of 25OH vitamin D continues to grow in clinical laboratories. The aim of this multicenter study was to compare the results of seven automated commercial immunoassays with a reference HPLC technique. Methods: One hundred and twenty consecutive outpatient serum samples were centrifuged, divided in aliquots, frozen and shipped to the participating laboratories. 25OH Vita - min D was measured with a reference HPLC system and with seven automated commercial immunoassays (Roche Cobas E601, Beckman Coulter Unicel DXI 800, Ortho Vitros ES, DiaSorin Liaison, Siemens Advia Centaur, Abbott Architect i System and IDS iSYS). Results: Compared to the reference method, the regression coefficients ranged from 0.923 to 0.961 (all p<0.001). The slope of Deming fit ranged from 0.95 to 1.06, whereas the intercept was comprised between -15.2 and 9.2 nmol/L. The bias from the reference HPLC technique varied from 14.5 to 8.7 nmol/L. The minimum performance goal for bias was slightly exceeded by only one immunoassay. The agreement between HPLC and the different immunoassays at 50 nmol/L 25OH Vitamin D varied between 0.61 and 0.85 (all p<0.001). The percentage of samples below this cut-off was significantly different with only one immunoassay. Conclusions: The excellent correlation with the reference HPLC technique attests that all seven automated immuno - assays may be reliably used for routine assessment of 25OH-D in clinical laboratories. The significant bias among the different methods seems mostly attributable to the lack of standardization and calls for additional efforts for improving harmonization of 25OH-D immunoassays. Kratok sadr žaj Uvod: Merenje 250H vitamins D sve se češće obavlja u kliničkim laboratorijama. Cilj ove multicentricne studije bio je da se rezultati sedam automatizovanih komercijalnih imunoeseja uporede sa referentnom tehnikom HPLC. Metode: Sto dvadeset uzoraka seruma od uzastopnih pacijenata koji su posetili kliniku centrifugirano je, podeljeno u alikvote, smrznuto i poslato laboratorijama koje su učestvovale u istraživanju. Nivo 250H vitamina D meren je pomoću referentnog sistema HPLC i pomoću sedam automatizovanih komercijalnih imunoeseja (Roche Cobas E601, Beckman Coulter Unicel DXI 800, Ortho Vitros ES, DiaSorin Liaison, Siemens Advia Centaur, Abbott Architect i System i IDS iSYS). Rezultati: U đenju sa referentnim metodom, koeficijenti regresije kretali su se između 0,923 i 0,961 (svuda p<0,001). Nagib za Demingovu regresiju kretao se od 0,95 do 1,06, dok je kriva obuhvatila područje između -15,2 i 9,2 nmol/L. Odstupanje od referentne tehnike HPLC kretalo se od -14,5 do 8,7 nmol/L. Minimalni domet za odstupanje blago je prešao samo jedan imunoesej. Slaganje između HPLC i različitih imunoeseja pri koncentraciji od 50 nmol/L 250H vitamina D variralo je izmedu 0,61 i 0,85 (svuda p<0,001). Procenat uzoraka ispod ove cut-off vrednosti znacajno se razlikovao samoza jedan imunoesej. Zaključak: Odlična korelacija sa referentnom tehnikom HPLC potvrđuje da se svih sedam automatizovanih imunoeseja mogu sa sigurnošću koristiti za rutinsko određivanje nivoa 250H-D u kliničkim laboratorijama. Značajno odstupanje izmedu različitih metoda po svoj prilici se može uglavnom pripisati nedostatku standardizacije i zahteva dodatne napore kako bi se popravila harmonizacija imunoeseja za 250H-D