A new NIH-supported study has demonstrated that “routine lab tests may not be useful in making a long COVID diagnosis for people who have symptoms of the condition.”
Long COVID itself “encompasses a wide spectrum of symptoms and health conditions that persist for months or years after infection from SARS-CoV-2, the virus that causes COVID-19. No validated clinical biomarkers of long COVID have been found to date, so diagnosing the condition currently requires gathering a detailed medical history and having patients take a physical exam to understand their symptoms, as well as getting laboratory work to rule out other causes.”
The study was conducted in order to “determine whether a SARS-CoV-2 infection led to changes in biomarkers, such as platelet counts or protein in the urine, in individuals with a prior SARS-CoV-2 infection, compared to those without prior infection.” To that end, over 10,000 adults were recruited across the U.S. from October 2021 to October 2023, 8,746 of whom had a previous SARS-CoV-2 infection and 1,348 of whom had never been infected. 19% of the study population had long COVID.
Lab tests “detected markedly few differences in biomarkers between those with prior infection and those without.” Researchers also noted “slightly elevated increases in uACR, a measure of low kidney function, in participants with previous infection, but those were only seen in a minority of people in that group and may have resulted from severity of the initial infection.”
Researchers also looked at the infected group “to determine the differences between those who developed long COVID versus those who did not,” but among participants with prior infection, “the study found no meaningful differences in lab test results between the two groups.”
