Why do roughly 1 in 3 COVID-19 patients experience symptoms lasting a month or more? And which newly diagnosed patients will develop so-called “long COVID”?

Researchers may be approaching answers with the discovery that reduced levels of certain antibodies in the blood may help predict who will suffer long COVID. The discovery could potentially lead to a blood test early on to detect long COVID risk in newly diagnosed patients and guide treatment.

The research from the University of Zurich was published on Nature Communications and reported by NBC News. Reduced levels of two immunoglobulins, IgM and IgG3, when combined with factors like middle age and asthma, were 75% effective in predicting long COVID, according to Dr. Onur Boyman, an author of the new study and a researcher in the department of immunology at University Hospital Zurich.

“These individuals might have a disadvantage from the start,” he told NBC News, “and then due to their asthmatic background, they might also react slightly differently to viruses, which then leads to a misguided immune response.”

Although long COVID isn’t an official diagnosis, roughly one-third of patients may experience symptoms for at least a month.

Research began early in the pandemic

Boyman’s team looked at more than 500 COVID patients beginning in early 2020 during the first wave of the pandemic, following patients through the acute phase of infection, then for six months and then for a year. The work preceded the identification of omicron variant and did not account for vaccination status. The study did not account for vaccination status, and many of the patients  became ill before vaccinations were available.

If confirmed in larger studies, the research could be “an important step forward towards directing resources in post COVID-19 clinics to those who need them the most,” Dr. Kartik Sehgal, a long COVID researcher and medical oncologist at the Dana-Farber Cancer Institute in Boston, wrote in an email to NBC News.

Another recent study identified risk factors that may predict whether a person will develop long COVID, including Epstein-Barr virus infection, certain autoantibodies, type 2 diabetes, and a high quantity of SARS-CoV-2 genetic material in the blood. More than 200 patients provided blood samples and nasal swabs over several months beginning at diagnosis.

We supply researchers with COVID-19 biospecimens, including variants

This research is yet another example of biospecimens’ ability to tell us a lot about a patient’s health status and future.

iSpecimen provides life sciences researchers with a range of biospecimens from patients with COVID-19 and other diseases as well as from healthy controls. Just a few weeks ago, we announced a partnership with a New York reference lab that genetically sequences swabs to identify Omicron, Delta and other COVID-19 variants.

In early 2020, iSpecimen began sending serum samples to the U.S. Centers for Disease Control and Prevention (“CDC”) to help researchers monitor antibody development for possible guidance on immunity. iSpecimen has provided the CDC with 600 SARS-CoV-2-positive serum samples and 100 negative serum samples. In addition, iSpecimen has provided other federal agencies and private companies custom COVID-19 collections, which are often complex and complement the more immediate availability of remnant or banked samples. Overall, iSpecimen has delivered more than 15,000 specimens for more than 200 COVID-related projects since the start of the pandemic.

Learn about the iSpecimen Marketplace where you can browse millions of richly annotated, de-identified human tissue and biofluid biospecimens, in addition to hematopoietic and immune cell products and COVID-19 samples. You can join for free.