We used the commercially available Multitest (R) CMI to assess the response of 100 adults hospitalized with community-acquired pneumonia to the following seven antigens: tetanus toxoid, diphtheria toxoid, Streptococcus, Proteus, tuberculin, Candida, and trichophyton. Thirty-one of the patients responded to one or more of these antigens and survived their acute illness. Of the Multitest (R) CMI negative patients, 49 lived and 20 died. A comparison of the three groups revealed that the 31 patients with positive tests were significantly younger and had a higher mean serum albumin than did those with negative tests who died. Multivariate analysis revealed that a positive Multitest (R) CMI and the albumin level were independent predictors of survival. A positive Multitest (R) CMI identified a less seriously ill group of patients as evidenced by 100% survival, by a very low rate of complications (0.18/patient), and by less utilization of resources (fewer hemograms and chest radiographs). Thus a positive Multitest (R) CMI may identify patients who could be discharged earlier, and a negative test should target its patients for more aggressive therapy.