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Background: The harmonization status of most tumor markers (TMs) is unknown. We report a feasibility study performed to determine whether external quality assessment (EQA) programs can be used to obtain insights into the current harmonization status of the tumor markers α-fetoprotein (AFP), prostate specific antigen (PSA), carcinoembryonic antigen (CEA), cancer antigen (CA)125, CA15-3 and CA19-9., Methods: EQA sample results provided by 6 EQA providers (INSTAND [Germany], Korean Association of External Quality Assessment Service [KEQAS, South Korea], National Center for Clinical Laboratories [NCCL, China], United Kingdom National External Quality Assessment Service [UK NEQAS, United Kingdom], Stichting Kwaliteitsbewaking Medische Laboratoriumdiagnostiek [SKML, the Netherlands], and the Royal College of Pathologists of Australasia Quality Assurance Programs [RCPAQAP, Australia]) between 2020 and 2021 were used. The consensus means, calculated from the measurement procedures present in all EQA programs (Abbott Alinity, Beckman Coulter DxI, Roche Cobas, and Siemens Atellica), was used as reference values. Per measurement procedure, the relative difference between consensus mean for each EQA sample and the mean of all patient-pool-based EQA samples were calculated and compared to minimum, desirable, and optimal allowable bias criteria based on biological variation., Results: Between 19040 (CA15-3) and 25398 (PSA) individual results and 56 (PSA) to 76 (AFP) unique EQA samples were included in the final analysis. The mean differences with the consensus mean of patient-pool-based EQA samples for all measurement procedures were within the optimum bias criterion for AFP, the desirable bias for PSA, and the minimum bias criterion for CEA. However, CEA results <8 µg/L exceeded the minimum bias criterion. For CA125, CA15-3, and CA19-9, the harmonization status was outside the minimum bias criterion, with systematic differences identified., Conclusions: This study provides relevant information about the current harmonization status of 6 tumor markers. A pilot harmonization investigation for CEA, CA125, CA15-3, and CA19-9 would be desirable., (© Association for Diagnostics & Laboratory Medicine 2024. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Background: Serum Chromogranin A (CgA) is widely used as a biomarker for pancreatic neuroendocrine tumors (PanNETs). The aim of this study was to investigate the value of CgA as a diagnostic and prognostic marker for well-differentiated PanNETs., Methods: Patients with well-differentiated PanNET and a baseline CgA measurement, between 2011 and 2016 were reviewed. The diagnostic value was determined by comparing CgA values from patients with PanNETs to those with other pancreatic neoplasms and healthy controls. The Kaplan-Meier method was used to investigate the CgA prognostic significance., Results: Ninety-nine patients met inclusion criteria. As a diagnostic marker, CgA had a sensitivity of 66%, specificity of 95%, and overall accuracy of 71%. The use of PPIs was associated with a higher CgA level (p = 0.015). When excluding patients on PPIs, CgA accuracy in distinguishing PanNETs from other pancreatic neoplasms was 66%, the sensitivity and specificity were 60% and 75% respectively. Elevated CgA (p = 0.004), Ki67% (p < 0.001), tumor grade (p < 0.001) and stage of disease (p = 0.036) were associated with disease-specific survival., Conclusion: CgA has a limited role as a diagnostic biomarker for well-differentiated PanNETs. An elevated CgA level may have prognostic value but its role should be further investigated with respect to other known pathological factors., (Copyright © 2018 International Hepato-Pancreato-Biliary Association Inc. Published by Elsevier Ltd. All rights reserved.)

Objective: To assess whether the use of a laboratory test specific for intact human chorionic gonadotropin (hCG) would reduce the number of false-positive pregnancy test results., Methods: From October 21, 2014, to January 20, 2015, and April 1, 2015, to June 2, 2015, all serum samples sent for pregnancy screening at a large cancer center with a value of 5 milli-international units/mL or greater total β-hCG were frozen and stored and then retested using intact hCG reagent. We compared the accuracy of total β-hCG and intact hCG results for the diagnosis of clinically confirmed pregnancy. A negative test was defined as 14 milli-international units/mL or less, our current institutional cutoff. We also assessed a cutoff of less than 5 milli-international units/mL, a historical cutoff to rule out pregnancy., Results: We performed intact hCG testing on 64 patient samples, of which 34 had originally resulted positive when tested for total β-hCG. These included 21 cases of clinically confirmed pregnancy and 13 false-positive cases. No women were pregnant when their intact hCG concentration was 14 milli-international units/mL or less, and all pregnancies were detected at and above this concentration. Intact hCG reduced the number of false-positive pregnancy test results from 13 to 1, a 92% reduction (95% CI 64-99%), corresponding to a reduction in the false-positive rate from 38% (95% CI 22-56%) to 3% (95% CI 1-15%)., Conclusion: The use of intact hCG reagent in patients with cancer reduces the rate of false-positive pregnancy test results without increasing the rate of false-negative test results.