Background:Despite several synovial fluid biomarkers for the diagnosis of periprosthetic joint infection (PJI) having been investigated, point-of-care (POC) tests using these biomarkers are not widely available. Synovial calprotectin has recently been reported to effectively exclude the diagnosis of PJI. Thus, the objective of this study was to test the value of a calprotectin POC test for PJI diagnosis in patients undergoing total knee arthroplasty (TKA) using the 2013 Musculoskeletal Infection Society (MSIS) PJI diagnosis criteria as the gold standard.Methods:Synovial fluid samples were prospectively collected from 123 patients who underwent revision TKA at 2 institutions within the same health-care system from October 2018 to January 2020. The study was conducted under institutional review board approval. Data collection comprised demographic, clinical, and laboratory data in compliance with the MSIS criteria. Synovial fluid samples were analyzed by calprotectin POC tests in accordance with the manufacturer’s instructions. Revisions were categorized as septic or aseptic using MSIS criteria by 2 independent reviewers blinded to the calprotectin results. Calprotectin test performance characteristics with sensitivities, specificities, positive predictive values, negative predictive values, and areas under the receiver operating characteristic curve (AUC) were calculated for 2 different PJI diagnosis scenarios: (1) a threshold of ≥50 mg/L, and (2) a threshold of ≥14 mg/L.Results:According to the MSIS criteria, 53 revision TKAs were septic and 70 revision TKAs were aseptic. In the ≥50-mg/mL threshold scenario, the calprotectin POC performance showed a sensitivity of 98.1%, a specificity of 95.7%, a positive predictive value of 94.5%, a negative predictive value of 98.5%, and an AUC of 0.969. In the ≥14-mg/mL threshold scenario, the sensitivity was 98.1%, the specificity was 87.1%, the positive predictive value was 85.2%, the negative predictive value was 98.4%, and the AUC was 0.926.Conclusions:The calprotectin POC test has excellent PJI diagnostic characteristics, including high sensitivity and specificity in patients undergoing revision TKA. This test could be effectively implemented as a rule-out test. However, further investigations with larger cohorts are necessary to validate these results.Level of Evidence:Diagnostic Level I. See Instructions for Authors for a complete description of levels of evidence.

Common causes of chronic upper gastrointestinal bleeding include oesophageal varices, gastroduodenal ulcers and malignancy, and patients mostly present with iron deficiency type anaemia. We present the case of a 60-year-old lady who presented with iron deficiency anaemia and on investigation was found to have a large duodenal polyp requiring surgical excision. On histological examination, the polyp was revealed to be a lipoma. We review the recent literature and formulate a management plan for this rare entity.

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Introduction Serum androstenedione (ASD) is a useful biomarker in the diagnostic workup of hyperandrogenism, congenital adrenal hyperplasia, premature adrenarche, and polycystic ovary syndrome (PCOS). Recently, the Elecsys ASD assay (Roche Diagnostics), a competitive electrochemiluminescence immunoassay, became available in the US. Herein, the analytical and clinical performance of the Elecsys ASD assay was tested and compared with the Immulite assay (our current assay) and an LC-MS/MS assay (the gold standard) using deidentified residual patient specimens. Method In this study, the linearity, analytical measuring range (AMR), precision, and accuracy of the Elecsys ASD assay (cobas e602 analyzer) were tested. ASD from 40 deidentified residual serum/plasma samples was measured and compared between the Elecsys assay, the Immulite assay, and an LC-MS/MS assay. The reference intervals (RIs) provided by Roche for healthy male (0.280-1.52 ng/mL), healthy female (0.490-1.31 ng/mL), postmenopausal female (0.187-1.07 ng/mL), healthy children (<0.519 ng/mL), and patients with PCOS (0.645-3.47 ng/mL) were tested with at least 20 specimens, according to CLSI C28A3. Statistical analysis was performed using EP evaluator and R program. Result and conclusion The assay had a linear response across the AMR (0.3-10.0 ng/mL). The inter- and intra-assay coefficients of variation measured at multiple concentrations were less than 4.5% and 2.0%, respectively. The Elecsys ASD assay had an excellent correlation with the LC-MS/MS assay with a mean bias of -0.0542 ng/mL (-2%). The Immulite assay had a mean bias of 1.15 ng/mL (44%) and 1.22 ng/mL (32%) compared to the LC-MS/MS and Elecsys ASD assays, respectively. The Roche recommended RIs for healthy males and postmenopausal females were successfully verified in our patient population. However, the ASD concentrations for the healthy children were outside of the suggested RI, with concentrations up to 1.41 ng/mL. Therefore, the RIs for healthy children were adopted from RIs established using the same LC-MS/MS method used for method comparison. RI verification for the healthy female group also failed since many low ASD values were observed. Instead, a RI of < 1.30 ng/mL was established using 60 deidentified residual serum/plasma specimens. Finally, a separate RI for the PCOS group was not established since it may not provide useful clinical information due to the heterogeneity of the group. Unlike some published studies, hormone therapies such as oral contraceptive pills did not cause a significant decrease in ASD in patient specimens (p=0.4967). Overall, the Elecsys ASD assay has superior comparability to the LC-MS/MS assay than the Immulite assay. We were unable to verify the applicability of the RIs recommended by Roche for healthy females and children, warranting the need to establish or transfer them. When RI verification is challenging due to limited qualified specimens, transferring from an LC-MS/MS established RI is possible as long as the methods are comparable.