The list system can reduce the waiting time and number of consultations in a centralized primary care centre that provides out of hours medical care.

Objective - To study the waiting time and number of consultations of the patients who required out of hours medical care from a centralized primary care centre before and after the introduction of a list system. Design - Non-controlled intervention study. A questionnaire, completed by receptionists, concerning all out of hours general practice consultations for one week each month during two separate years (in 1990 with no list system and in 1993 with list system in operation). Setting - One health centre in central Finland in a region with 39 495 inhabitants. Subjects - All patients contacting the health centre to request medical help during out of hours work. Outcome measures - Consultation rates by age and sex of the patients and their waiting time before seeing the GP. Results - Zn 1990, the average out of hours consultation rate per 1000 inhabitants per year was 826 for women and 819 for men. These figures were reduced by 271 for women (95% CI 262-280) and 305 for men (95% CI 297-314) in 1993. The mean waiting time was 55 min in 1990 and 32 min in 1993 (p<0.001). Conclusion - The introduction of a list system leads to more effective primary care services.