Caveat emptor The American Journal of Medicine Allan Jaffe, MD  The American Journal of Medicine  Volume 115, Issue 3, Pages 241-244 (August 2003) DOI: 10.1016/S0002-9343(03)00361-9

Figure Effects of precision (coefficient of variability [CV]) on confidence intervals for a given value. With a cutoff value of 0.1 μg/L and a CV of 10%, one can be 95% confident that the values of 0.085 μg/L and 0.115 μg/L (3 SDs apart) are different. With a CV of 50%, one would need values of 0.025 μg/L and 0.175 μg/L to know with 95% confidence that the values are different. Reproduced with permission from Hollander JE, Apple FS, Jaffe AS. Emergency Physician's Guide to the Use of Cardiac Troponins and Other Cardiac Markers in the Diagnosis and Management of Patients with Chest Pain. Trevose, PA: Medical Education Group LLC, Euro RSCG; 2003:11. The American Journal of Medicine 2003 115, 241-244DOI: (10.1016/S0002-9343(03)00361-9)