Effectiveness of Rapid Antigen Testing in Forensic Cases of Severe Acute Respiratory Syndrome Coronavirus 2 Infection, Including Delta Variant.

ABSTRACT: The polymerase chain reaction is indispensable for diagnosing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in forensic cases. However, studies regarding the effectiveness of rapid antigen testing (RAT) in forensic cases remain limited. Therefore, we investigated the efficacy of RAT compared with reverse-transcription quantitative polymerase chain reaction (RT-qPCR) for confirming SARS-CoV-2 infection (including the delta variant). Before the external examination or autopsy, we collected samples from the nasopharyngeal mucosa, which were then assessed via RAT (QuickNavi COVID-19 Ag kit, QuickNavi-Flu+COVID-19 Ag kit) and RT-qPCR. Reverse-transcription quantitative polymerase chain reaction results were positive in 73 of 1255 cases, and 21 cases were identified as those of delta variants. Low RT-qPCR threshold cycle value cases and delta variant infections were more likely to result in coronavirus disease-related deaths. The sensitivity of the QuickNavi COVID-19 Ag kit was 76.32%, and that of the QuickNavi-Flu+COVID-19 Ag kit was 77.14%. The specificity of both RATs was 100%. In QuickNavi COVID-19 Ag kit cases, delta variant cases showed lower sensitivity than non-delta variant cases, even for a similar viral load. Thus, RAT in forensic cases is sufficiently useful as a screening test for SARS-CoV-2 infection. However, RAT carries a risk of false negatives, especially for delta variant cases.

Relationship between N-terminal pro-brain natriuretic peptide concentration and heart-type fatty acid-binding protein in postmortem urine.

The clinical use of N-terminal pro-brain natriuretic peptide (NT-proBNP) and blood concentrations of heart-type fatty acid-binding protein (HFABP) is well-established in diagnosing heart conditions. However, their applicability in forensics is controversial due to postmortem changes. NT-proBNP and HFABP are excreted in the urine due to their small molecular weights and may be found in postmortem urine samples; however, their correlation has not been evaluated. In this study, we compared the concentrations of urinary NT-proBNP and HFABP in 386 forensic autopsy cases. The urinary NT-proBNP levels were significantly higher in acute myocardial infarction (AMI), congestive heart failure (CHF), sepsis, and hyperthermia cases, with the highest levels in CHF cases. Similarly, HFABP concentration was significantly higher in CHF, sepsis, and hyperthermia cases, with the highest level observed in hyperthermia cases. However, the difference in urinary HFABP levels between the AMI and control cases was not significant. Our analysis revealed a correlation between postmortem urine NT-proBNP and HFABP levels, and the NT-proBNP/HFABP ratio was high in patients with CHF and sepsis cases and low in those with hyperthermia. The difference between the ratios was possibly due to the combined release of ventricular myocardial cells in response to ventricular wall stress and myocardial injury for NT-proBNP, as well as myocardial and skeletal muscle injuries for HFABP. This study, for the first time, demonstrates the utility of postmortem measurements of urinary NT-proBNP and HFABP levels, offering valuable insights for improving the accuracy of postmortem diagnosis in forensic medicine.

Postmortem pericardial fluid sLOX-1 levels and LOX-1 immunostaining in forensic specimens: Relation to cause of death.

Lectin-like oxidized LDL receptor-1 (LOX-1) is the endothelial receptor for oxidized LDL. This receptor's extracellular domain is released into the blood as soluble LOX-1 (sLOX-1) and has been linked to ischemic heart disease (IHD), cerebrovascular diseases (CVDs), obesity, and diabetes. We recently reported that sLOX-1 fluid levels in postmortem pericardial fluid were comparable to clinical values in live patients and that significant increases in sLOX-1 were observed in patients with IHD. However, postmortem serum and urine sLOX-1 levels were higher than serum levels in living patients. Here, we conducted LOX-1 immunostaining in forensic specimens (aorta and heart) and evaluated pericardial fluid sLOX-1 in 221 medicolegal autopsy cases (67 IHD, 11 CVD, 17 inflammatory diseases, and 126 control cases) with a postmortem interval < 72 h to assess the diagnostic efficiency of postmortem pericardial fluid sLOX-1. Furthermore, we evaluated the relationships between pericardial fluid sLOX-1 and body mass index (BMI), blood HbA1c, serum C-reactive protein (CRP), high-density lipoprotein cholesterol (HDL-C), and low-density-lipoprotein cholesterol (LDL-C). LOX-1 immunostaining positivity was found in the aortic intima. Pericardial fluid sLOX-1 levels were considerably higher in patients with IHD and CVD. However, there were no significant differences in patients with inflammatory diseases and controls. No associations between pericardial fluid sLOX-1 and BMI, HbA1c, CRP, HDL-C, or LDL-C were found. These results indicate sLOX-1 utility in the postmortem diagnosis of IHD and CVD.