[Limitations of the protein profile for diagnostic orientation in initial internal medicine consultation. Prospective...

Determination of the protein profile of orientation (PPO) is now considered by some authors as a means of improving the diagnosis in internal medicine. The feasibility of systematizing this practice was investigated in 76 outpatients (79 included, three excluded secondarily) seen for pathology of undetermined diagnosis. The 79 patients (mean age: 52 years) underwent the classical biological explorations plus PPO. The physicians were divided into two groups (seniors and assistants). Two complete clinical files were established for each patient, with one difference concerning inflammatory and immunologic data: one file included the minimum number of tests considered necessary by the physician and the other the complete PPO (nine proteins). Each file (with or without PPO) was randomly distributed to one of two physicians in the same group. Each physician filled in a diagnostic evaluation sheet indicating whether there was organic pathology or not, the main diagnosis (inflammatory, neoplastic, infectious or other), the secondary diagnosis and the hypothesis of probability. The relevance of the clinical opinion was analyzed by an internal medicine specialist from outside the department with 40 years of clinical experience. The duration of symptoms before the medical visit was from 3 weeks to 5 years (mean 6 months). A diagnosis of organic pathology was reached for three out of four patients. Sixty-seven patients were seen again after a minimum of 6 months, and nine were lost to follow-up. Diagnostic efficiency was no greater for cases with PPO, which appears to be a biological examination of second intention. We suggest that the term "protein profile of orientation" be replaced by "broad protein profile."