by atd gc ms grading of rejection endomyocardial biopsies were jointly evaluated by two pathologists who graded the degree of rejection employing a standard rating scale from 0 no evidence of rejection through ia ib ii and iiia 41 masking procedures sorbent traps were analyzed for vocs in the laboratory by technical assistants who had no knowledge of the pathological findings the pathologists reviewing the biopsies had no knowledge of the results of the breath test analysis of data all chromatograms of breath and air were automatically downloaded into computer based spreadsheets and then into a computer based relational data base the breath methylated alkane contour bmac was determined in all subjects human subjects and endomyocardial biopsies all human subjects recruited for the research were able to donate a breath sample into the bca and none reported any discomfort or adverse effects from the breath collection procedure two pathologists graded rejection in the endomyocardial biopsies grade 0 118 210 56 2 ia 48 210 22 9 ib 14 210 6 7 ii 23 210 10 9 and iiia 7 210 3 3 only one of the age matched normal controls and three of the transplant recipients were smokers so the potential effects of smoking were not analyzed separately breath vocs differences between heart transplant recipients and normals the mean bmacs of heart transplant recipients with grade 0 rejection i e no histological evidence of rejection and age matched normal controls are shown in fig8 and table 3 breath vocs differences between heart transplant recipients with different grades of rejection the mean bmacs of heart transplant recipients with grade 0 grade ia and ib grade ii and grade iiia rejection are shown in fig9 and table 4 determination of sensitivity and specificity the.