Logistic discrimination was used to assess the effectiveness of serum myoglobin (Mb), creatine kinase (CK), and hemopexin (H) measurements in identifying Duchenne muscular dystrophy (DMD) carriers. Subjects included 36 obligate carriers, 46 age-matched control women, 30 mothers of isolated cases, and 14 DMD patients. The percentages of obligate carriers with logistic carrier probabilities exceeding the upper normal 95th centile (or 97.5th centile) were: CK alone, 63% (50%); Mb alone, 65% (62%); CK and Mb, 66% (62%); CK and H, 78% (65%); CK H and Mb, 72% (65%). In this study, Mb identified more carriers than CK at the 97.5% level, but there was no advantage in using Mb measurements with CK. CK provided slightly better overall separation of the control and carrier groups than Mb. CK, Mb, and H in combination provided significantly better separation than CK and H, or CK alone.