In this investigation, the results from a spot test investigation comprising 3182 emergency ambulance services (AU) from three geographical regions with different degrees of urbanization are presented: The Danish capital (Municipality of Copenhagen), a large provincial town (Odense) and a rural district with smaller towns (the County of Ringkøbing). The conditions of the patients were assessed by the ambulance staff: 7-12% of the patients transported had visible haemorrhage, 5-8% were unconscious, 4-7% were cyanotic, 2-3% had seizures and 1-2% had pareses. The serious cases tended to be most frequent in the least urbanized regions. Registration of the therapeutic efforts by the ambulance staff prior to and during transport revealed that 15-33% of the patients did not receive any treatment. The commonest forms of treatment consisted of oxygen treatment (13-18%), treatment for shock (8-12%), Nato position (4-16%) and stopping of haemorrhage (7-12%). No differences were observed between the three geographic regions except that fewer patients in the capital received treatment. In cases of emergency ambulance services employing signals, medical support was available in 22% of the cases in Copenhagen, mainly by means of medically staffed ambulances. In the County of Ringkøbing, doctors, usually the doctor-on-call, participated in 27% of these services while medical support was only available in 2% of the cases in Odense. Registration of the diagnoses by the hospitals which received the patients revealed that the commonest group of diagnoses were injuries (36-44%) and cardiovascular disease (14-21%).(ABSTRACT TRUNCATED AT 250 WORDS)