New Sputum Test Reveals Chronic Lung Disease Risks Sooner

According to researchers taking part in the nationwide SPIROMICS study on COPD, measuring two key airway mucins, MUC5AC and MUC5B, along with total mucin levels found in sputum samples, may help to identify people at greater risk of developing COPD and other chronic lung conditions earlier than is currently possible with standard pulmonary function testing.

Dubbed the “Quantitative Mucin Index (MUCQ) of the lung,” the test can also be used to track disease progression.

“MUCQ allows us to detect underlying mucus abnormalities before significant lung damage appears on standard lung function tests,” explained lead study author Mehmet Kesimer, PhD, from the UNC School of Medicine. “With an objective, biology-based measurement, we can now issue far more compelling evidence that will help physicians provide diagnoses and treatments sooner, rather than later.”

In a study conducted among SPIROMICS participants with and without chronic bronchitis, the investigators found that those with higher MUCQ scores had worse lung function, small airway disease, chronic bronchitis symptoms, and a greater risk of future COPD exacerbations than those with lower scores.

Overall, the MUCQ was superior to total mucin concentration alone in distinguishing patients with chronic bronchitis from those without.

Symptomatic smokers with normal lung function were also found to have higher scores, leading the authors to suggest the test could be used to incentivize smokers to kick the habit as well.

“In the clinic, doctors always tell patients to stop smoking, but behavior change is hard,” said Dr. Kesimer. “Being able to show a patient an objective numeric value — like their MUCQ score — especially when their lung function still appears normal, can be far more convincing.”

The study was published by NEJM Evidence.

Highlighted in RC Buzz March 2, 2026