[Respiratory functional tests in professional asthma. Value of realistic tests (author's transl)]

The diagnosis of professional asthma raises problems that cannot be solved in many cases either by anamnestic data or by skin tests: realistic can then prove very useful. Reproducing in the laboratory the professional surroundings, these tests consist in studying the ventilatory variations induced by allergens inhaled during work. The authors report the results of these examinations done on 30 patients whose realistic tests were performed with controls of ventilatory variations by body plethysmography. Confirming the professional etiology of asthma was reached 16 times out of 30 by these tests. These substances concern: chemical products (9 cases), dust of plant or animal origin (4 cases), various saw dusts (2 cases), tissue extracts (1 case). These results enabled the authors to underline the interest of these tests which nevertheless have limits: a negative realistic test is not enough to eliminate this diagnosis, because it is not always possible to reproduce exactly the workshop atmosphere in the laboratory. On the contrary, a positive test does not necessarily mean that the asthma is truly and predominantly a professional asthma. Results must therefore always be interpreted in relation with the clinical context, although the mechanism involved is known to be variable. A positivity can be attributed to an allergic mechanism, a non immunological release of mediators, or simple irritative reactions. In spite of these draw-backs, realistic tests represent one of the best means of diagnosing professional asthma.