The medical clinic at Moín Container Terminal in Costa Rica has three or four doctors and a nurse. They work in rotation shifts and are open 24 hours a day to dockworkers. The goal was to study the traits of workers sent for drug and alcohol testing at a medical clinic. This happened over 5 months because of concerns about abuse.

Materials and methods
Anonymous patient records from the medical clinic were analyzed. Of a total of 3050 visits to the clinic (n=673) were selected be tested for doping (ICD-10 Z03.6).

Results
The number of seafarers found positive for alcohol was n=2 (0.3%) and n=31(4.6%) positive for drugs. Other reasons to visit the clinic were mostly diseases of the musculoskeletal system, abnormal clinical and laboratory symptoms, injuries, and digestive system diseases.

Conclusions
The number of seafarers who tested positive for alcohol and drugs was low. However, this is still important for safe driving in the harbor. We could not assess the relative risks associated with different work tasks. This was due to a lack of information about the population distribution in those tasks. Inconsistencies in the coding system make analysis difficult. A drop-down menu could help improve the digital registration system and reduce errors.
Keywords:
Shipping; drugs; alcohol; epidemiology; container; transport.