30th Jun 2020

COVID-19 FAQ: How biomarkers can help predict mild illness or need for intensive care?

30th Jun 2020

Curated by Endre Szvetnik

Scientists are proposing to use biomarkers – molecules occurring in the blood – to inform doctors about the likely disease progress of COVID-19 patients.

Biomarkers in the blood can inform doctors about expected disease severity

Using biomarker data, clinicians can make an early decision on how to treat people arriving at the hospital, potentially saving lives. According to a systematic review, there is clear evidence that the levels of certain biomarkers change according to the severity of coronavirus infection. A key biomarker is a C-reactive protein (CRP) which the liver produces in response to inflammation. Patients suffering from severe cases have significantly higher levels of CRP than the normal level of 10 mg/L and, the likelihood of severe COVID-19 increases to 41.8 Mg/L in the blood.

Another important biomarker is IL-6, the most common type of a cytokine (a protein regulating inflammation). IL-6 plays a key role in the damaging and exaggerated immune reaction called ‘cytokine storm’ that has been linked to deaths in COVID-19 patients). Studies have revealed that IL-6 levels can be three times higher in severe than in mild cases. IL-6 levels rise sharply at the beginning of a severe infection, which allows doctors to quickly identify serious cases. In addition to the systematic study, a new research paper has found 3 of the 27 further biomarkers, that has not been linked to COVID-19 before, are associated with IL-6.
 
Meanwhile, the levels of an enzyme, lactate dehydrogenase (LDH) can be indicative of viral infection and lung damage, such as pneumonia triggered by COVID-19. Its levels can be over 60% higher in patients who are transferred to intensive care than in others. D-dimers are biomarkers that can indicate a higher risk of mortality. They are small protein fragments appearing in the blood after a blood clot is formed during COVID-19. (Read our earlier FAQ about how blood clotting and consequent strokes affect critical COVID-19 patients).
 

How is the testing done in the hospital? Tests can range from a few minutes to several hours and their results can help doctors to act quickly to save lives. Results can help to assess which patients are at critical risk, potentially need ventilation and progress to intensive care. CRP blood tests can take 2-5 minutes, to reveal if a patient has a serious infection. IL-6 blood tests have just become faster - a major medical manufacturer claims their FDA-approved technology can reveal a result in 18 minutes. This will give doctors the option to prescribe IL-6 inhibitors, that - according to a study - have reduced inflammation and the need for ventilation in COVID-19 pneumonia patients. Due to some COVID-19 patients suffering cardiac arrests, doctors also test for troponin, a protein, which appears in the blood to indicate heart damage. The test is fast but has to be repeated to monitor changes in levels, so it can take up 6 to 24 hours. Doctors are also testing patients for signs of acute kidney injury, which is common in critically ill COVID-19 sufferers. Blood tests are fast, but biomarkers in urine also has to be monitored, so the process can last for up to 24 hours.

Here is the current state of science on a Sparrho pinboard. NB: The pinboard contains research papers that have not been peer-reviewed yet, meaning that they have not gone through the standard scientific validation process yet.

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Curated by

Endre Szvetnik

Endre Szvetnik is Senior Editor at Sparrho. Endre works with Sparrho Heroes to curate, translate and disseminate scientific research to the wider public.

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