Objective: This paper is a continuation of the study on the validity of equations of predicted value (PV) for the Brazilian population. A comparison was made between the equations proposed by Mallozi and by Polgar for the Brazilian population, which are mainly used in the United States and Europe. Methods: PVs of 185 patients of both sexes (89 boys and 96 girls), ages between 6 and 17 years, were analyzed. For each subject, the PVs for forced vital capacity (FVC), forced expiratory volume at 1 sec. (FEV1), and the medium expiratory flow (MEF) were calculated according to the equations proposed by Mallozi and Polgar. Results were compared. Diagnoses were made according to the Brazilian Consensus of Spirometry. Results: The PV-M for FVC is 0.38% higher for boys and 2.19% higher for girls than that determined by Polgar. The PV-P for FEV1 is 6.67% (p < 0.05) lower for girls, suggesting an underassessment of the obstructive impairment. For boys, a mean lower value of 7.26% as compared to the VT-M is at the limit of significance (0.05 < p < 0.01). No significant difference between the two equations analyzed was found for MEF. Conclusions: The PVs for CVF and VEF1 for Brazilian children, according to Mallozzi, are significantly different when compared to those published by authors like Polgar. As a result, the authors found that Mallozzi's equations are more likely to detect obstructive impairment and less likely to diagnose restrictive ventilatory insufficiency.

Keywords: Spirometry. Vital capacity. Forced expiratory volume. Maximal medium expiratory flow rate. Case-control studies