BONE MARROW WILL GIVE HIGH BACKGROUND DUE TO BLOOD , HOWEVER I WILL TELL YOU THAT ON BOTH THE NEXES AND BENCHMARK WE ONLY INCUBATE 4 MINUTES ON BOTH THE KAPPA AND LAMBDA AND GET NICE RESULTS, YOU COULD TRY DILUTING YOUR ANTIBODY OUT OR YOU CAN LOWER INCUBATION TIMES IN 2-4 MIN INCREMENTS TO SEE IF THIS LOWERS BACKGROUND. DANA