[Laser nephelometry. A better methodology?].

Nephelometric assays (LN) are known since several years ago. Laser beam immunonephelometric analysis (He-Ne: 640 nm), are a sophistication of the spectrophotometers. Nephelometry was the first method to make use of narrow-angle light scattering and a laser beam. It was made 2500 +/- 200 determinations of human fluids for IgG, IgA, IgM, C3 and C4, both LN and RID (radial immunodiffusion method). Human patients had the following characteristics: 18-55 years old, both sexes and with different pulmonary pathologies (Bronchial asthma, Bronchitis, Tuberculosis, Emphysema, Fibrosis, Extrinsic allergic alveolitis). We found a greater sensitivity and a shorter analysis time for LN than for RID. On the other hand, Nephelometry gave different values to the radial immunodiffusion method for all the proteins evaluated.