Background The aims of this study were: (1) to calculate reliable thyroid stimulating hormone (TSH) reference intervals using laboratory databases; (2) to evaluate the relationship between TSH, sex ...and age values in different large Italian populations. Methods The TSH values stored in the laboratory information system of clinical laboratories of four Italian city hospitals, including 146,801 TSH measurements (with the respective age and sex data of individuals) were taken in consideration. Assuming a log-normal distribution, to log-transformed TSH values were applied the Dixon's iterative principle in order to exclude the outliers. At the end of this iterative process 142,821 log-transformed TSH results remained. The four clinical laboratories measured serum TSH concentrations using the same TSH immunoassay method (Access TSH 3rd IS, using UniCel DxI platform). Results The TSH reference interval calculated in the present study (0.362-5.280 mIU/L) is similar to that suggested by the manufacturer for the Access TSH 3rd IS assay (0.45-5.33 mIU/L). TSH values in females were significantly higher than in males (females: mean=2.06 mIU/L; standard deviation SD=1.26 mIU/L; n=101,243; males: mean=1.92 mIU/L; SD=1.19 mIU/L; n=41,578; p<0.0001). Moreover, a negative linear relationship was observed between TSH throughout all interval age values (from 0 to 105 years). Conclusions The results of the present multicenter study confirm that data mining techniques can be used to calculate clinically useful reference intervals for TSH. From a pathophysiological point of view, our results suggest that some Northern populations of Italy might still suffer some harmful effects on the thyroid gland due to mild to moderate iodine intake deficiency. Specific clinical trials are needed to confirm these results.
This study was aimed to evaluate the analytical performance of the novel Diazyme procalcitonin (PCT) immunoturbidimetric assay on Beckman Coulter AU5800.
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.
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.
Diazyme PCT appears to be a reliable assay for diagnosis and management of critical care patients susceptible to severe bacterial infections.
Our laboratory performs procalcitonin (PCT) assays on a Brahms KRYPTOR analyzer with the Brahms PCT sensitive Kryptor kit. In this study, we wanted to compare the assays obtained in this way with the ...ones performed on the LIAISON
XL. From January to May 2017, 171 samples were analyzed, of which 65 from female patients (age: 22-98 years) and 106 from male patients (age: 16-97 years). The PCT determination was performed using the LIAISON
XL and KRYPTOR analyzers, by chemiluminescence (Chemiluminescence immunoassay-CLIA) (LIAISON
BRAHMS PCT
II GEN) and immunofluorescence (Brahms PCT sensitive Kryptor) assay, respectively. For the LIAISON
BRAHMS PCT
II GEN, 52% of the results were placed between 0.0 and 0.5 ng/mL, 18% between 0.5 and 2.0 ng/mL, and 30% between 2.0 and 100 ng/mL; the mean was 4.09 ng/mL, the median 0.456 ng/mL, the maximum value 97.2 ng/mL, and the minimum value 0.02 ng/mL. For the Brahms PCT sensitive Kryptor, 55% of the results were positioned between 0.0 and 0.5 ng/mL, 21% between 0.5 and 2.0 ng/mL, and 24% between 2.0 and 100 ng/mL; the mean was 3.72 ng/mL, the median 0.39 ng/mL, the maximum value 103 ng/mL, and the minimum value 0.01 ng/mL. The mean of the results obtained with the two methods showed no significant differences (3.717 for Kryptor and 4.094 for LIAISON
). PCT assay with Brahms reagents, both on the Kryptor and LIAISON
XL platforms, offers excellent performance in terms of sensitivity and specificity.
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).
One hundred serum samples from in-patients with PCT values between 0.10 and 58.7ng/mL were divided into aliquots and tested with the nine different reagents and analyzers. BRAHMS PCT Kryptor results were used as reference.
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 ±1.02ng/mL, except for Vidas (2.70ng/mL). The agreement at three clinically relevant cut-offs was optimal: between 83–98% at 0.50ng/mL, 90–97% at 2.0ng/mL, and 98% at 10ng/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 ±0.9ng/mL, acceptable agreement at 0.5ng/mL (>82%), and high concordance at the 2.0ng/mL (>97%) and 10ng/mL (>98%) cut-offs.
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 measurement of 25OH vitamin D continues to grow in clinical laboratories. The aim of this multi-center study was to compare the results of seven automated commercial immunoassays with a reference ...HPLC technique.
One hundred and twenty consecutive outpatient serum samples were centrifuged, divided in aliquots, frozen and shipped to the participating laboratories. 25OH Vitamin 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).
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.
The excellent correlation with the reference HPLC technique attests that all seven automated immunoassays 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.
Summary
Background:
The patients with episodes of chest pain and no electrocardiographic or biomarker abnormalities are currently monitored and subjected to non-invasive testing. Stress ...echocardiography is one of the most often used provocative tests, being the most cost- and risk-effective imaging technique. Some concerns about this technique have been raised regarding potential drug-induced myocardial injury. Our study hence aimed to establish whether or not dipyridamole stress echocardiography elicits release of troponin I (TnI) and T (TnT), as reliable bio-markers of myocardiocyte injury.
Methods:
Thirty-two patients, after exclusion of ongoing acute coronary syndrome (ACS) during evaluation in the emergency department (ED), were studied with echocar-diography both at the baseline and after pharmacological stress with dipyridamole.
Results:
All subjects had biomarkers assessment immediately before the stress-test (T1), 1 h from conclusion of the test (T2), and 6 h afterwards (T3). Cardio specific troponins were assessed with one contemporary-sensitive (TnI) and two highly-sensitive (HS) methods (HS-TnI and HS-TnT). The concentration of TnI, HS-TnI and HS-TnT did not differ throughout the three time points. At no time point the concentration of either HS-TnI or HS-TnT was significantly different among patients with negative or positive stress test.
Conclusions:
The data shows that dipyridamole stress testing does not trigger release of troponin in patients with and without inducible reversible ischemia.
This prospective study was planned to assess whether red blood cell (RBC) parameters may be useful in diagnostics of patients with brain injury after mild head trauma. The RBC count, hemoglobin, ...hematocrit, RBC distribution width (RDW) and mean corpuscular volume were assessed in all consecutive patients admitted to the emergency department over 3 months with isolate, mild head trauma and Glasgow coma scale between 14-15, and seen within 3 h from trauma. The final study population consisted of 54 patients (21 women and 33 men; median age=48 years), of whom, 13 (24%) with positive computed tomography (CT). No significant difference was found for age (P=0.45) and gender (P=0.21) distribution between CT positive and negative patients. No significant difference was observed for the median concentration of all the RBC parameters tested, and the preva- lence of anemia (P=0.37) and anysocytosis (P=0.40) did not differ significantly between patients with positive and negative CT. Red blood cell distribution width assessment upon patient admission did not provide a significant contribution to final diagnosis of mild head injury in receiver operating characteristic curve analysis area under the curve (AUC) 0.51; P=0.44. We conclude that assessment of RDW does not provide useful clinical information for diagnosing brain injury after mild head trauma.
The Italian Society of Clinical Biochemistry (SIBioC) and the Italian Section of the European Ligand Assay Society (ELAS) have recently promoted a multicenter study (Italian hs-cTnI Study) with the ...aim to accurately evaluate analytical performances and reference values of the most popular cTnI methods commercially available in Italy. The aim of this article is to report the results of the Italian hs-cTnI Study concerning the evaluation of the 99th percentile URL and reference change (RCV) values around the 99th URL of the Access cTnI method.
Heparinized plasma samples were collected from 1306 healthy adult volunteers by 8 Italian clinical centers. Every center collected from 50 to 150 plasma samples from healthy adult subjects. All volunteers denied the presence of chronic or acute diseases and had normal values of routine laboratory tests (including creatinine, electrolytes, glucose and blood counts). An older cohort of 457 adult subjects (mean age 63.0 years; SD 8.1 years, minimum 47 years, maximum 86 years) underwent also ECG and cardiac imaging analysis in order to exclude the presence of asymptomatic cardiac disease.
The results of the present study confirm that the Access hsTnI method using the DxI platform satisfies the two criteria required by international guidelines for high-sensitivity methods for cTn assay. Furthermore, the results of this study confirm that the calculation of the 99th percentile URL values are greatly affected not only by age and sex of the reference population, but also by the statistical approach used for calculation of cTnI distribution parameters.
•99th percentile URL is considered as the cut-off for detection of myocardial injury and diagnosis of myocardial infarction.•The evaluation of 99th percentile URL is affected by age, sex and the experimental approach used for calculation.•An accurate evaluation of 99th percentile URL and reference change values of a high-sensitivity cTnI method is reported.•The results of this study should be taken into consideration by clinicians for clinical interpretation of cTnI assay.
The detection of an increase and/or decrease of cardiac troponin (cTnI) values, with at least one value above the 99th percentile of the upper reference limit (URL) have a central role in acute ...myocardial infarction (AMI) diagnosis. The employment of sex specific 99th percentile URLs and High-sensitivity (Hs) assays are recommended. We assessed sex specific 99th percentile URL for Access Hs-cTnI and AccuTnI3+ (Beckman Coulter) using European donor reference population following recent International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) recommendations.
300 males and 300 females plasma samples were collected. Both chemiluminescent immunoenzymatic assays were performed on UniCel DxI 800 platform (Beckman Coulter).
For Access hsTnI, the observed sex-specific 99th percentile URLs were 5.5 (90% CI: 4.4–7.6) for females and 13.9 ng/L (90% CI: 7.4–17.4) for males. For AccuTnI+3 we could not establish them because the assay couldn't report detectable values of troponin for most of the analyzed samples.
The sex-specific 99th percentile URLs established for Access hsTnI assay were significantly lower than those declared by the manufacturer caused by the different choice of population selection, age groups and sample types: for those reasons, we maintain the 99th URLs provided by manufacturer.
•Sex specific 99th upper reference limits for troponins are recommended by guidelines.•Study on 300 males and 300 females from European donor reference population.•We gave sex specific cut-offs for high-sensitivity troponin; not for contemporary one.•Our sex-specific reference limits were lower than those provided by the manufacturers.•We maintain the 99th upper reference limits declared by the manufacturer.
Background
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.
Methods
We studied 25 members of the soccer team Parma F.C., playing in Italian major football league. Blood and saliva samples were collected at fasting, before a regular training session. Cortisol, total and free testosterone, as well as the ratio between free testosterone and cortisol, were assessed in paired serum and saliva samples, and their results were compared.
Results
An excellent correlation was found between serum and saliva cortisol (r = 0.751; P < 0.001). A significant correlation was also observed between free testosterone in serum and saliva (r = 0.590; P = 0.002), whereas no significant correlation was found between total testosterone in serum and saliva (r = 0.181; P = 0.387). A significant correlation was found for the free testosterone to cortisol ratio in serum and saliva (r = 0.43; P = 0.031). All athletes (25/25; 100%) declared that they would feel more comfortable to have saliva rather than blood serially collected.
Conclusions
The results of this study suggest that measurement of free testosterone and cortisol in saliva may be seen as a reliable alternative to their assessment in serum.
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