The analytical performance of a new immunometric CK-MB assay from Novo Biolabs was evaluated in three hospitals. Comparisons were made with another immunometric assay, an immune inhibition/precipitation technique, an immune inhibition method, and a column separation method. The Novo assay exhibited good precision (CV 3-7%) at all concentration levels tested (6-150 micrograms/L) and was found to be linear over the range 0-200 micrograms/L. Comparison of the Novo kit with the other methods using patients' sera showed acceptable correlation between the methods over a wide concentration range (r = 0.96-0.99). We conclude that the assay is a useful adjunct to the specific measurement of CK-MB, particularly in routine laboratories with a high throughput of such determinations.