Several years ago, I earned extra income by performing insurance physicals, which included obtaining blood samples. From this experience, I learned certain 'things' that cause life insurance policies to be denied. My answer is based on that experience and not current knowledge of insurance regs, OK?
HIV positive
positive ANA
illegal drugs
certain cardiac emzymes--the C3 complement, if I recall correctly
elevated liver enzymes
elevated PSA
The potential client should request to be retested by a physician of his or her choice and to appeal or reapply for life insurance; the life insurance company, however, is not under any obligation to offer the life insurance policy. The benefit would be the removal of denial of insurance based on findings in an insurance exam should the findings be inaccurate, with the exception of the ANA which often fluctuates negative and positive.
Hope that helps!