- A two-step test can predict the severity of Covid-19
- It can do this between the sixth and eighth day after the onset of symptoms
- It can also help to establish the medication a patient may need before severe disease sets in
A new study has found that a two-step prognostic test can predict the severity of Covid-19, and the worst outcomes of the disease.
The research published in mSphere shows that the testing tool can predict severe disease specificity with an accuracy rate of 83.6%.
Testing the test
The researchers mapped antibodies in the plasma of 86 Covid-19 patients experiencing a wide range of disease states associated with severe disease, as well as admission to the intensive care unit (ICU), requiring a ventilator and death.
The scientists set up a two-step test. The first step involves the polymerase chain reaction, which is a DNA sequence from confirmed Covid-19 patients. The second step involves enzyme-linked immunosorbent assays (ELISA), measuring the binding of antigens from the plasma.
The researchers pooled the plasma, diluted it 100-fold, then applied it as a coating on a microtiter plate as the target antigen for binding to the phage-displayed epitopes. Epitopes are the part of an antigen molecule to which an antibody attaches itself.
They compiled a list of antibodies that might correlate with the worse prognosis and ultimately focused on one that attaches to epitope nine on the nucleocapsid protein. They also developed a tool that applied data to factors including age, sex, and pre-existing health conditions to produce a disease risk factor score.
The study findings show that those with epitope 9 antibodies were more likely to have prolonged illness and worse outcomes than people without the antibodies.
The data demonstrate that patients with a disease risk factor score greater than three are 13.42 times more likely to have severe Covid-19 disease symptoms.
The antibodies appear early in the course of the disease – six to eight days after symptom onset. This early detection could be used to triage and treat Covid-19 prior to the onset of the most severe symptoms of the disease.
“The results lay the groundwork for a new type of Covid-19 prognostic to allow early identification and triage of high-risk patients,” the authors write.
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