Key Takeaways
No lab test can be used to diagnose Long COVID
Out of 25 standard blood and urine tests, none could sort people with Long COVID from healthy people
Future research will focus on coming up with new lab tests
TUESDAY, Aug. 13, 2024 (HealthDay News) -- No lab test can reliably indicate whether or not someone is suffering from Long COVID, a major new study finds.
None of 25 standard lab blood and urine tests proved useful in diagnosing Long COVID, according to results published Aug. 13 in the Annals of Internal Medicine.
"Our study shows patients can have severe Long COVID with normal lab results,” said lead researcher Dr. Kristine Erlandson, a professor of infectious diseases at the University of Colorado Anschutz Medical Campus.
“This suggests doctors should not focus on the results of blood panels to diagnose Long COVID, but should focus more on symptoms and ways to help patients get relief by treating their symptoms," Erlandson added in a university news release.
About 7% of adults in the United States -- nearly 18 million people -- have Long COVID, researchers said in background notes.
Long COVID typically develops weeks after an initial infection with COVID-19, and can involve a plethora of symptoms that plague a person for months or even years, according to the U.S. Centers for Disease Control and Prevention.
For this study, researchers analyzed data from more than 10,000 people participating in a National Institutes of Health (NIH) initiative called RECOVER, which is aimed at better understanding Long COVID. About 86% of the participants have had a prior COVID infection.
Earlier research of RECOVER participants produced a set of 12 long-term symptoms that can be used to diagnose Long COVID.
These symptoms -- ranging from "brain fog" to chest pain -- are linked to the effects of the coronavirus on multiple organ systems. Those results were published last May in the Journal of the American Medical Association.
As a next step, researchers decided to focus on lab tests that might be used to definitively diagnose people who have Long COVID.
“Our challenge is to discover biomarkers that can help us quickly and accurately diagnose long COVID to ensure people struggling with this disease receive the most appropriate care as soon as possible,” said Dr. David Goff, director of cardiovascular sciences at the National Heart, Lung, and Blood Institute (NHLBI).
“Long COVID symptoms can prevent someone from returning to work or school, and may even make everyday tasks a burden, so the ability for rapid diagnosis is key,” Goff added.
The team compared lab test results between people with and without a prior COVID infection; between people with and without a Long COVID diagnosis; and between people with common Long COVID symptoms and those unlikely to have Long COVID.
In all cases, an exhaustive list of routine blood and urine lab tests could not help in making a Long COVID diagnosis, said senior researcher Dr. Grace McComsey, a professor and dean of clinical and translational research at Case Western Reserve University in Cleveland.
“Until a reliable biomarker is found, the best diagnostic modality... remains the old-fashioned history-taking and clinical assessment,” McComsey added.
The next step will be to see if blood and spinal fluid samples taken from RECOVER participants can be used to develop newfangled lab tests for Long COVID, Erlandson said.
The set of 12 symptoms now used to diagnose long COVID include: post-exertional malaise; fatigue; brain fog; dizziness; gastrointestinal symptoms; heart palpitations; changes in sexual desire or capacity; affected smell or taste; thirst; chronic cough; chest pain; and abnormal movements.
More information
The U.S. Centers for Disease Control and Prevention has more on Long COVID symptoms.
SOURCE: University of Colorado, news release, Aug. 12, 2024
