OBJECTIVES: To investigate the referral behavior of primary care physicians (PCPs) and specialists when encountering patients with undiagnosed symptoms.

METHODS: This cross-sectional study surveyed PCPs and specialists in Europe (France, Germany, Italy, Spain, United Kingdom [UK]). Participants were recruited via physician panels in January 2023 and completed an online questionnaire.

RESULTS: The study involved 478 PCPs and 1,132 specialists: hematology/oncology (176), internal medicine (112), cardiology (106), neurology (99), pediatrics (88), dermatology (82), ophthalmology (77), endocrinology/diabetology (77), rheumatology (71), gastroenterology/hepatology (67), obstetrics/gynecology (63), urology (53), nephrology (41), and infectious diseases (20). When unable to diagnose symptoms, 11.9% of PCPs and 24.7% of specialists (rising to 41.4% of neurologists) frequently suspected a rare disease. Physicians referred patients after the initial visit (16.0% overall, 11.1% PCPs, 18.1% specialists [range: 6.0% gastroenterologists, 35.1% ophthalmologists]), second visit (43.7% overall, 42.5% PCPs, 44.2% specialists), or third or later visit (40.3% overall, 46.4% PCPs, 37.7% specialists). Waiting for (or inconclusive) test results was the primary reason for delaying referral: 54.7% overall, 49.9% of PCPs, and 56.9% of specialists (range: 44.9% neurologists, 76.3% nephrologists). Primary reasons differed by country: waiting for (or inconclusive) test results (range: 42.1% Germany, 58.3% Italy), preferring to wait/watch (range: 9% Italy, 20% France), delays in scheduling appointments with other physicians (range: 9.9% Italy, 18.5% Germany). Secondary reasons included symptoms not being applicable to the physician/not wanting to interfere (PCPs: 4.24%; specialists: 10.9%; p<0.001) and long waiting lists (72.2% PCPs, 46.5% specialists, p<0.001). Country differences were observed: desire of patients to not see another physician (range: 10.0% UK, 33.8% Germany), symptoms not applicable to physician/not wanting to interfere (range: 4.3% Italy, 16.2% Germany), and scheduling complexities/paperwork (range: 7.3% France, 17.6% Spain).

CONCLUSIONS: Differences in referral behavior exist among PCPs and specialists, within specialties, and across countries. Improved referral procedures could benefit patient care.