Section 4.96 - Special provisions regarding evaluation of respiratory conditions(a)Rating coexisting respiratory conditions. Ratings under diagnostic codes 6600 through 6817 and 6822 through 6847 will not be combined with each other. Where there is lung or pleural involvement, ratings under diagnostic codes 6819 and 6820 will not be combined with each other or with diagnostic codes 6600 through 6817 or 6822 through 6847. A single rating will be assigned under the diagnostic code which reflects the predominant disability with elevation to the next higher evaluation where the severity of the overall disability warrants such elevation. However, in cases protected by the provisions of Pub. L. 90-493 , the graduated ratings of 50 and 30 percent for inactive tuberculosis will not be elevated.(b)Rating "protected" tuberculosis cases. Public Law 90-493 repealed section 356 of title 38, United States Code which had provided graduated ratings for inactive tuberculosis. The repealed section, however, still applies to the case of any veteran who on August 19, 1968, was receiving or entitled to receive compensation for tuberculosis. The use of the protective provisions of Pub. L. 90-493 should be mentioned in the discussion portion of all ratings in which these provisions are applied. For application in rating cases in which the protective provisions of Pub. L. 90-493 apply the former evaluations pertaining to pulmonary tuberculosis are retained in § 4.97 .(c)Special monthly compensation. When evaluating any claim involving complete organic aphonia, refer to § 3.350 of this chapter to determine whether the veteran may be entitled to special monthly compensation. Footnotes in the schedule indicate conditions which potentially establish entitlement to special monthly compensation; however, there are other conditions in this section which under certain circumstances also establish entitlement to special monthly compensation.(d)Special provisions for the application of evaluation criteria for diagnostic codes 6600, 6603, 6604, 6825-6833, and 6840-6845.(1) Pulmonary function tests (PFT's) are required to evaluate these conditions except: (i) When the results of a maximum exercise capacity test are of record and are 20 ml/kg/min or less. If a maximum exercise capacity test is not of record, evaluate based on alternative criteria.(ii) When pulmonary hypertension (documented by an echocardiogram or cardiac catheterization), cor pulmonale, or right ventricular hypertrophy has been diagnosed.(iii) When there have been one or more episodes of acute respiratory failure.(iv) When outpatient oxygen therapy is required.(2) If the DLCO (SB) (Diffusion Capacity of the Lung for Carbon Monoxide by the Single Breath Method) test is not of record, evaluate based on alternative criteria as long as the examiner states why the test would not be useful or valid in a particular case.(3) When the PFT's are not consistent with clinical findings, evaluate based on the PFT's unless the examiner states why they are not a valid indication of respiratory functional impairment in a particular case.(4) Post-bronchodilator studies are required when PFT's are done for disability evaluation purposes except when the results of pre-bronchodilator pulmonary function tests are normal or when the examiner determines that post-bronchodilator studies should not be done and states why.(5) When evaluating based on PFT's, use post-bronchodilator results in applying the evaluation criteria in the rating schedule unless the post-bronchodilator results were poorer than the pre-bronchodilator results. In those cases, use the pre-bronchodilator values for rating purposes.(6) When there is a disparity between the results of different PFT's (FEV-1 (Forced Expiratory Volume in one second), FVC (Forced Vital Capacity), etc.), so that the level of evaluation would differ depending on which test result is used, use the test result that the examiner states most accurately reflects the level of disability.(7) If the FEV-1 and the FVC are both greater than 100 percent, do not assign a compensable evaluation based on a decreased FEV-1/FVC ratio.34 FR 5062, Mar. 11, 1969, as amended at 61 FR 46727, Sept. 5, 1996; 71 FR 52459 , Sept. 6, 2006 Authority: 38 U.S.C. 1155