Canine real-time detection of SARS-CoV-2 infections in the context of a mass screening event.

INTRODUCTION: Previous research demonstrated that medical scent detection dogs have the ability to distinguish SARS-CoV-2 positive from negative samples with high diagnostic accuracy. To deploy these dogs as a reliable screening method, it is mandatory to examine if canines maintain their high diagnostic accuracy in real-life screening settings. We conducted a study to evaluate the performance of medical scent detection dogs under real-life circumstances. METHODS: Eight dogs were trained to detect SARS-CoV-2 RT-qPCR-positive samples. Four concerts with a total of 2802 participants were held to evaluate canines' performance in screening individuals for SARS-CoV-2 infection. Sweat samples were taken from all participants and presented in a line-up setting. In addition, every participant had been tested with a SARS-CoV-2 specific rapid antigen test and a RT-qPCR and they provided information regarding age, sex, vaccination status and medical disease history. The participants' infection status was unknown at the time of canine testing. Safety measures such as mask wearing and distance keeping were ensured. RESULTS: The SARS-CoV-2 detection dogs achieved a diagnostic specificity of 99.93% (95% CI 99.74% to 99.99%) and a sensitivity of 81.58% (95% CI 66.58% to 90.78%), respectively. The overall rate of concordant results was 99.68%. The majority of the study population was vaccinated with varying vaccines and vaccination schemes, while several participants had chronic diseases and were under chronic medication. This did not influence dogs' decisions. CONCLUSION: Our results demonstrate that SARS-CoV-2 scent detection dogs achieved high diagnostic accuracy in a real-life scenario. The vaccination status, previous SARS-CoV-2 infection, chronic disease and medication of the participants did not influence the performance of the dogs in detecting the acute infection. This indicates that dogs provide a fast and reliable screening option for public events in which high-throughput screening is required.

Albumin combined with Mannitol impairs whole blood coagulation and platelet function in vitro.

BACKGROUND: The indication of hydroxyethyl starch is currently under critical discussion and albumin 5% (ALB) has an increasing use in the operating theatre. Therefore, ALB is routinely used in neurosurgical procedures and often combined with mannitol 20% (MAN). Purpose of this in-vitro study was to determine the influence of the combination of MAN and ALB on blood coagulation and platelet function. METHODS: Twenty-two healthy volunteers were included into this study and 21 analyzed. Blood was obtained and diluted into five groups: 1) 7% dilution with MAN; 2) 10% dilution with ALB; 3) 17% dilution with isotonic balanced electrolyte solution; 4) 17% dilution with MAN+ALB; and 5) undiluted blood as control group (CON). Rotational thrombelastometry via ROTEM® (EXTEM™/FIBTEM™ Test; SABIC, Riyad, Saudi Arabia) and thrombocyte aggregometry via Multiplate® (Roche Diagnostics, Grenzach-Wyhlen, Germany) (ASPI, ADP and TRAP-test) were used to detect differences within the intervention groups and compared to the control group. RESULTS: The maximum clot firmness in the FIBTEM™ Test (SABIC) decreased under the normal range with the combination of MAN+ALB: 8 mm (5.5-11) compared to CON: 15 mm (12.5-20), P<0.05. Platelet function (ADP test) showed significant decreases for ALB: 51 AUC (40-84) and MAN+ALB: 54 AUC (41-68) compared to CON: 92 AUC (75-101), P<0.05. Except in clotting time all other EXTEM™ tests (SABIC) of MAN+ALB subgroup showed significant impairment on blood coagulation compared to the control group. CONCLUSIONS: In this in-vitro study clinically relevant dilutions of MAN+ALB showed a significant inhibition of blood coagulation and platelet function. Further in-vivo studies are necessary to confirm these results.

Mannitol and the Combination of Mannitol and Gelatin Impair Whole Blood Coagulation and the Platelet Function In Vitro.

OBJECTIVE: Mannitol 20% and succinylated gelatin 4% are routinely used in neurosurgical procedures. The aim of this in vitro study was to explore the influence of both agents on blood coagulation and platelet function. METHODS: Blood from 21 healthy volunteers was obtained and then diluted so as to form five groups: (1) 7% dilution with mannitol; (2) 10% dilution with gelatin; (3) 17% dilution with isotonic balanced electrolyte solution; (4) 17% dilution with mannitol+gelatin; and (5) undiluted blood. The extrinsic thrombelastometry (EXTEM) and fibrin thrombelastometry (FIBTEM) tests were examined by rotational thrombelastometry via ROTEM®, and thrombocyte aggregometry with the aspirin inhibiting- (ASPI), adenosine diphosphate- (ADP), and thrombin-activating protein (TRAP) tests performed by Multiplate. RESULTS: In the EXTEM test clot formation time, the alpha angle, and maximum clot firmness were significantly reduced by mannitol and the combination of mannitol with gelatin. The platelet function tested in the ADP test was also significantly reduced with this combination. CONCLUSION: In this in vitro study, clinically relevant dilutions of mannitol and gelatin showed a significant inhibition of whole blood coagulation and the platelet function, which could be detrimental in neurosurgical settings.