Positive results of a recent clinical trial suggest that blood tests may offer key benefits in the initial screening for obstructive sleep apnea (OSA). The study, which involved 264 male adult patients from six institutions, revealed that screening for changes in three specific biomarkers may be useful in helping to identify people with OSA. The results of the study were published in the peer-reviewed journal, Nature and Science of Sleep, with the anticipation that use of these objective blood tests will improve screening accuracy and timely diagnosis as well as patient management. Diagnostic medical equipment company Beckman Coulter—whose clinical research department is listed as one of the author’s affiliations—offers this panel of three assays on fully automated platforms in the United States. Hemoglobin A1c (HbA1c) and C-reactive protein (CRP) are chemistry tests on the Synchron and AU systems while erythropoietin (EPO) is on the DxI and Access 2 immunoassay systems.

“The study results demonstrate that sleep apnea induces a characteristic signature cluster of blood biomarker changes,” says principal investigator and lead author Wesley Elon Fleming, MD, diplomate, American Board of Sleep Medicine and Neurology, Sleep Center Orange County, Irvine, California, in a release. “Concurrent elevations of HbA1c, CRP, and EPO levels should generate a high index of suspicion of obstructive sleep apnea, and thus, may be useful as an initial screening tool in adult males.”

Jon-Erik Holty, MD, MS, Stanford Medical School/VA Palo Alto Health Care System, says, “The combination of these three blood tests correlates with the severity of disease and may assist sleep centers in identifying and triaging patients for diagnosis and treatment. Undiagnosed and untreated sleep-apnea patients place a significant clinical and economic burden on the healthcare system.”

Rohit Budhiraja, MD, Harvard Medical School/Brigham and Women’s Hospital, says, “Important to note is that the blood tests were superior to standard screening methods, such as the Epworth Sleepiness Scale (ESS) and STOP-Bang questionnaires in identifying obstructive sleep apnea.” Additionally, the blood tests demonstrated superiority over the use of body mass index (BMI) as an indicator in non-obese patients—a significant finding, given that up to one-half of patients with sleep apnea are not obese.

Edith Mensah-Osman, MD, PhD, MBA, president/CEO and director of medical research at EENA Comprehensive Neurology & Sleep Center, Boynton Beach, Florida, says, “The combination of the three identified biomarkers performed as well for asymptomatic patients as it did for symptomatic patients.”

Richard Bogan, MD, FCCP, FAASM, of Columbia, SC, says, “Patients at risk of sleep apnea are currently unlikely to be referred to a sleep center; only 30% of patients are cautioned about sleep apnea by their primary care provider, who is frequently the first contact for patients seeking a diagnosis.”

Michael Samoszuk, MD, a study co-author and chief medical officer at Beckman Coulter, the company that developed the blood tests, says, “Sleep apnea patients were found to have an increased probability of prediabetes and intermediate to high cardiovascular risk. Sleep apnea-induced hypoxemia is associated with increased EPO concentrations; hence, there is biological plausibility for including these three blood tests in the biomarker panel for sleep apnea.”

Dennis Hwang, MD, Kaiser Permanente Sleep Center, Fontana, Calif, says, “After diagnosis and treatment, improvements are observed in sleep quality, quality of life and blood pressure, which may reduce the risk of heart disease and chronic health conditions, and decrease healthcare utilization and cost.”