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Clinical practice guidelines for the management of germ cell tumors recommend the measurements of human chorionic gonadotropin (hCG) and/or free hCGβ subunit for earlier diagnosis/recognition of the residual disease, for the prognostic evaluation and for the post-chemotherapy surveillance. However, the marketed hCG assays are validated and approved only for pregnancy purposes, with the sole exception of the Elecsys 'hCG+β' assay (Roche Diagnostics), cleared in Europe for oncological application. Theoretically, the hCG assay design for oncological purposes should fulfil the recommendations of the International Society of Oncology and Biomarkers requiring the use of antibodies displaying an equimolar recognition of both intact hCG and hCGβ monomer. Further analytical requirements should also be considered, such as optimal analytical sensitivity to allow an early tumor detection and low cross-reactivity for luteinizing hormone (LH). For the Elecsys assay, the detection limit (0.2 U/L) and the reported cross-reactivity for LH (0.12%) may be considered adequate if compared with the recommended requirements. Another issue is the definition of decision limits for oncologic purposes. After 3 years of clinical experience using the Elecsys assay in the oncology setting, we were able to define limits partitioned by sex and age as follows: males <50 years, 0.3 U/L; males >50 years, 2.3 U/L; female <50 years, 2.1 U/L; female >50 years, 5.6 U/L. There is an urgent need to disseminate appropriate educational information and to boost the clinical use of selective, highly sensitive and precise assays, specifically manufactured for cancer application. [ABSTRACT FROM AUTHOR]

Several authors have recently claimed an excess in serum folate test ordering, suggesting phasing out it from clinical use. According to studies performed in countries undergoing folic acid fortification policies, it is indeed no more cost-effective to test folate in the face of deficiency prevalence < 1%. In this paper, we sought to evaluate request appropriateness, analytical issues, and cost-effectiveness of serum folate determination for clinical purposes in the European context, considering if evidence retrieved in fortified countries may be generalized. Studies performed in non-fortified countries have generally reported a suboptimal folate intake and suggest a remarkable prevalence of folate deficiency. Our internal data suggest that ~ 20%-25% of the subjects undergoing serum folate test are at risk for deficiency. However, a reliable evaluation of the risk for deficiency implies the knowledge of all issues related to the total testing process of folate measurement as well as the identification of the appropriate population in which to perform the test. The cost-effectiveness of the test is maximized when the request is oriented to subjects suggestive/at risk for deficiency, becoming low if the test is used as a screening tool or for monitoring of vitamin intake/supplementation. Because the individual folate status has a key role in ensuring normal development, physiologic growth, and maintenance of optimal health, the evaluation of its serum levels has to be retained in the clinical use in non-fortified countries, boosting for more appropriate request, and evidence from countries following fortification policies should be cautionary interpreted. [ABSTRACT FROM AUTHOR]

Background: The European In Vitro Diagnostics (IVD) directive requires traceability to reference methods and materials of analytes. It is a task of the profession to verify the trueness of results and IVD compatibility., Methods: The results of a trueness verification study by the European Communities Confederation of Clinical Chemistry (EC4) working group on creatinine standardization are described, in which 189 European laboratories analyzed serum creatinine in a commutable serum-based material, using analytical systems from seven companies. Values were targeted using isotope dilution gas chromatography/mass spectrometry. Results were tested on their compliance to a set of three criteria: trueness, i.e., no significant bias relative to the target value, between-laboratory variation and within-laboratory variation relative to the maximum allowable error., Results: For the lower and intermediate level, values differed significantly from the target value in the Jaffe and the dry chemistry methods. At the high level, dry chemistry yielded higher results. Between-laboratory coefficients of variation ranged from 4.37% to 8.74%. Total error budget was mainly consumed by the bias. Non-compensated Jaffe methods largely exceeded the total error budget. Best results were obtained for the enzymatic method. The dry chemistry method consumed a large part of its error budget due to calibration bias., Conclusions: Despite the European IVD directive and the growing needs for creatinine standardization, an unacceptable inter-laboratory variation was observed, which was mainly due to calibration differences. The calibration variation has major clinical consequences, in particular in pediatrics, where reference ranges for serum and plasma creatinine are low, and in the estimation of glomerular filtration rate.