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The "hook effect" or "prozone phenomenon" occurs when the concentration of a particular analyte saturates the antibodies used in the test, resulting in falsely low or negative results despite the presence of high analyte concentrations. We report two recent cases of hook effect encountered with a widely used immunoassay analyzer, the Siemens Atellica® IM1600. The first case involves a patient with advanced metastatic prostate cancer whose total PSA (tPSA) concentration dropped dramatically from his last biological control. The second case concerns a pregnant woman whose total HCG (ThCG) levels were also subject to the hook effect and who was found to have a molar pregnancy. In both cases, a dilution step enabled to overcome this analytical concern and to obtain a correct result. In addition, a comparison of the sensitivity of different immunoassay analyzers to this phenomenon was carried out. To avoid this analytical error, an additional dilution step should automatically be performed when there is a clinical suspicion of elevated levels of tumor or hormone markers. Finally, the most affected manufacturers should adapt their assays, accordingly.
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http://dx.doi.org/10.1016/j.plabm.2024.e00366 | DOI Listing |
NMR Biomed
October 2025
Department of Radiology, Shanghai Municipal Hospital of Traditional Chinese Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, People's Republic of China.
Chronic kidney disease (CKD) is an increasing global health problem, resulting in gradual loss of renal function and irreversible renal injury. The noninvasive detection, monitoring, and timely intervention of CKD might benefit the patients' prognosis. This study aims to assess renal functional injury in CKD patients by using magnetic resonance imaging (MRI) of quantitative susceptibility mapping (QSM).
View Article and Find Full Text PDFSci Bull (Beijing)
August 2025
Beijing Key Laboratory of Brainnetome and Brain-Computer Interface, Institute of Automation, Chinese Academy of Sciences, Beijing 100190, China; Brainnetome Center, Institute of Automation, Chinese Academy of Sciences, Beijing 100190, China; Xiaoxiang Institute for Brain Health and Yongzhou Central
J Cardiovasc Magn Reson
September 2025
Royal Brompton and Harefield Hospitals, part of Guy's and St Thomas' NHS Foundation Trust, London, UK; National Heart and Lung Institute, Imperial College London, UK. Electronic address:
Background: Serial perfusion cardiovascular magnetic resonance (CMR) in symptomatic patients undergoing coronary artery bypass grafting (CABG) may provide mechanistic insight into dynamic abnormalities of the myocardium.
Objectives: To assess how changes in cardiac reperfusion and remodelling associate with symptom improvement in patients undergoing CABG METHODS: Patients awaiting elective CABG completed serial quality of life questionnaires and detailed CMR at baseline and at 6-12 months post CABG as per protocol. Automated fully quantitative stress and rest myocardial blood flow was calculated, alongside assessment of the visual ischaemic burden.
J Cardiovasc Magn Reson
September 2025
Department of Radiology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA; Department of Biomedical Engineering, McCormick School of Engineering, Northwestern University, Evanston, IL, USA.
Background: Although a recently developed wideband perfusion sequence has shown diagnostically acceptable image quality and accurate myocardial blood flow (MBF) quantification at rest in patients with cardiac implanted electronic devices (CIEDs), its performance during vasodilator stress remains unproven. This study aims to determine whether the sequence produces diagnostically acceptable image quality during stress and is capable of quantitatively detecting abnormal stress MBF and myocardial perfusion reserve (MPR) in patients with implanted cardiodefibrillators (ICDs).
Methods: We enrolled 29 patients with an ICD (mean age = 63 ± 15 years, 17 males, 12 females) and 11 control patients (mean age = 50 ± 17 years, 6 males, 5 females; negative coronary artery disease; negative stress perfusion CMR; and no cardiac event one year post CMR) with an ICD taped below the left clavicle to mimic image artifacts.
Eur J Neurol
September 2025
Department of Neurology, Medical University of Innsbruck, Innsbruck, Austria.
Background: No standardized strategy for integrating κ-free light chain (κ-FLC) index into routine cerebrospinal fluid (CSF) diagnostics has yet been established.
Objective: To determine agreement between κ-FLC index and CSF-restricted oligoclonal bands (OCB), and to identify κ-FLC index range where second-line OCB testing is needed.
Methods: A retrospective analysis was conducted in patients who had κ-FLC measurement between December 2023 and December 2024 at the Medical University of Innsbruck.