A regional counselling service was established to handle all accidental blood exposures using a standardized protocol. Levels of risk were assessed using an algorithm. Accidents that posed a risk for the transmission of hepatitis B (HBV), hepatitis C (HCV) and human immunodeficiency virus (HIV) were classified as 'high risk', whereas accidents that posed a risk for HBV alone were classified as 'low risk'. Medical interventions were implemented according to the level of risk. During a one-year period, all accidents were registered and analysed for adherence to the standard protocol. In 2003, the centre handled 454 incidents. Of these, 36 (7.9%) incidents were assessed as no risk, 329 (72.5%) were assessed as low risk, and 67 (14.8%) were assessed as high risk. Due to incomplete registration, 22 (4.8%) incidents could not be analysed further. In total, 36% of the incidents with risk for HBV transmission and 40% of the incidents with risk for HCV and HIV transmission were not handled according to the proposed protocol. Breaches consisted of over-reaction (25/396) as well as insufficient response (123/396). Potentially inadequate treatment occurred for HIV postexposure prophylaxis in 12 of 63 incidents. Incomplete follow-up for HCV occurred in 11 of 63 incidents, and lack of HBV immunoglobulin administration occurred in five of 396 incidents, including three high-risk incidents. In 21 of 396 low-risk exposures, the breaches in protocol resulted from late reporting. It remains difficult to achieve an acceptable level of standardized care when using standard operational procedures. Documentation and evaluation of flaws are essential to improve the system.