Performance assessment of 11 commercial serological tests for SARS-CoV-2 on hospitalised COVID-19 patients

BACKGROUND

Commercial availability of serological tests to evaluate immunoglobulins (Ig) targeting severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has grown exponentially since the start of the coronavirus disease 2019 (COVID-19) outbreak. Thorough validation of these tests is important before use as epidemiological tools to infer seroprevalence in specific populations and as diagnostic tools to complement molecular approaches (e.g., quantitative reverse transcription-polymerase chain reaction).

METHODS

Commercial serological tests from 11 suppliers were assayed side-by-side using 126 samples from SARS-CoV-2-infected inpatients and 36 from healthy and HIV-infected individuals.

RESULTS

The majority of the tests assayed have >95% specificity. For the sensitivity calculation, samples were stratified by days since symptoms onset; sensitivity peaks at 16-21 days for IgM and IgA (maximum 91.2%, Euroimmun) and, dependant on the test, at 16-21 or >21 days for IgG (maximum 94.1%, Snibe). Data from semiquantitative tests show that patients with a severe clinical presentation have lower levels of Ig targeting SARS-CoV-2 at <10 days since symptoms onset and higher levels at >21 days, compared to patients with a non-severe presentation.

CONCLUSIONS

This study highlights the heterogeneity of sensitivity and generally high specificity of the serological tests and establishes a basis for their usefulness to complement diagnostic techniques and population seroprevalence studies.

1115 Ultra-slow low-dose thrombolytic therapy as an option of treatment in intracardiac thrombus: a case report

We present a case of a 57-year-old male with previously known primary severe mitral regurgitation, who was admitted to the ICU due to massive venous thromboembolism with associated right ventricle dysfunction and with two large mobile right atrial thrombi (2.4 x 1.5 cm and 3.6 x 3.7 cm). Despite of five days with a therapeutic aPTT achieved with unfractionated heparin (UFH), a TTE showed deterioration of the right ventricle systolic function, persistence of the right atrial masses with similar dimensions together with new mobile thrombi on the coronary sinus and on the right pulmonary artery. Due to deterioration of his clinical condition and given the refractoriness to the classical treatment with UFH, it was decided to administer an ultra-slow low-dose thrombolysis protocol, which consisted in a 24-hour infusion of 24 mg of alteplase at a rate of 1 mg per hour, without bolus. The treatment was continued by 48 consecutive hours, with clinical improvement and important reduction of the right atrial masses with resolution of the coronary sinus and right pulmonary artery thrombi. The patient started hypocoagulation with warfarin bridging with low molecular weight heparin (LMWH). Seven days after alteplase discontinuation there was complete resolution of the intracardiac thrombi. One month after ICU admission a successful mitral valve replacement surgery was conducted. Three months after discharge, the patient is in functional New York Heart Association (NYHA) class I with no cardiovascular events or hospitalizations. This case demonstrates that ultra-slow low-dose thrombolysis is a valid bailout treatment option in patients with large intracardiac thrombi refractory to anticoagulation.

Abstract 1115 Figure. TTE showing right atrial masses