When it comes to diagnosing post-COVID conditions (or so-called long COVID), Michael Saag, MD, of the University of Alabama at Birmingham, referred to the first line of an old Buffalo Springfield song in a call with clinicians on Thursday.

“There’s something happening here. What it is ain’t exactly clear,” Saag said.

CDC, which hosted the call, recently updated their interim guidance for healthcare professionals assessing and treating post-COVID conditions. While agency staff emphasized the heterogeneous nature of these conditions, they agreed most can be diagnosed and managed by primary care physicians in a patient-centered medical home model. They also should be evaluated in stages, beginning 4 weeks after a patient’s COVID infection, as some symptoms improve or resolve within 4 to 12 weeks.

Any symptoms lasting longer than 3 months may require specialist referrals or referral to multidisciplinary COVID care centers, said Jennifer Chevinsky, MD, of the CDC, though she urged caution when going outside the primary care model.

“Use a stepwise approach to other specialist referrals, while being aware of … the burden referrals may put on patients,” she noted, adding that the goal is to avoid “contradictory medical advice.”

Chevinsky recommended a “conservative diagnostic approach” in the first 4 to 12 weeks. She said that some patients might require diagnostic testing, but warned that not only can lab tests not distinguish post-COVID conditions, they are not required to diagnose post-COVID conditions.

Additional testing may be considered if symptoms persist for 12 weeks or more, she said.

There is also limited evidence on the utility of imaging for post-COVID conditions, so Chevinsky noted that this should be guided by “patient history and clinical findings.” More specialized tests, such as a cardiac MRI, might merit consultation with specialists.

A comprehensive rehabilitation plan might be helpful for some patients, though many post-COVID conditions can be improved through established evidence-based symptom management approaches to “optimize function and improve quality of life,” she said. These do not include herbal remedies, supplements, or other treatments that patients may have used to treat their symptoms.

As an ICD-10 code for post-COVID conditions does not yet exist, the CDC recommended documenting these conditions using B94.8 (sequelae of other specified infectious and parasitic diseases).

Alexis Vosooney, MD, of the American Academy of Family Physicians, offered a primary care physician’s perspective, noting the importance of validating the patient’s experiences, which CDC also suggested in its guidance.

She also encouraged clinicians to have a conversation about the patient’s goals, whether they are looking for an “answer” to their symptoms, to get back to where they were before COVID, or even if they have a fear of another disease process.

“Be transparent with patients. Admit there is a lot we don’t know about post-COVID symptoms and recovery,” Vosooney said, adding that it is “necessary to admit when we don’t have a lot of evidence.”

Distinguishing between post-COVID and other chronic conditions is necessary, she noted, citing the example of a patient with shortness of breath who had poorly controlled asthma prior to the pandemic.

Saag offered his perspective as both patient and clinician, having contracted COVID in March 2020 and working at a COVID clinic after he recovered. He stressed the importance of differentiating between post-COVID symptoms and post-intubation syndrome in patients who were on a ventilator.

Saag said he’s seen cases of post-COVID syndrome in prior marathon runners and people with no underlying conditions, who now “have trouble standing in the shower and walking to the mailbox.” Indeed, experts noted how post-COVID conditions can occur following an asymptomatic, mild, or severe infection. They can happen in all patients, from children to adults, and can be continuing, recurrent, or new symptoms can develop over time.

“In some ways, if you’ve seen one case of long COVID, you’ve seen one case of long COVID,” Saag noted.