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.

ObjectivesA 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 methodsOne 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.ResultsCompared 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.ConclusionsThe 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 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.

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.

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Diazyme PCT appears to be a reliable assay for diagnosis and management of critical care patients susceptible to severe bacterial infections.

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