[Analysis of errors in ICD 9 diagnostic classification in compliance with the Federal health care regulation].

In the present study the diagnosis from 1221 letters of discharge of the years 1986 and 1987 were additionally coded by the documentation doctor of the orthopaedic department and compared with the documentation sheets and the computer lists of the administration. Supplementary to this after one year there was carried out an additional coding of the letters by the documentation doctor. The transfer errors of the administration were amounting to 1.72 p.c. with regard to three digit numbers and to 11.87 p.c. with regard to four digit coding. During the repeated examination the documentation doctor made an error of 4.3 p.c. for the three digit coding and of 15.6 p.c. if the maximum coding was required. The corresponding errors of the house physicians for three digit numbers (maximum) were amounting to 8 p.c. (33.6 p.c.) for frequent diagnoses, to 28 p.c. (48.5 p.c.) for rare diagnoses and totally 13.7 p.c. (37.8 p.c.). In the present documentation validity and reliability still shows a good result compared to other studies. Nevertheless a documentation with an error rate to such an extend is of no use for a base documentation, and this error rate must be taken into consideration in the interpretation of global medical statistics. Automatic coding systems integrated into medical writing service seems to be the only help in view of removing these problems.