By Peter Laird, MD
It is interesting to understand that many of our practices in medicine are not based on clinical evidence, but instead on financial factors. However, with the advent of the bundled payment for renal dialysis services, the issue of lab tests which were previously separately billable, those related to routine dialysis evaluation are included in the bundle which shall put several tests at risk of reduced frequency. An interesting study quite timely from Louisville, Kentucky looked at the question of what is the optimal sampling frequency for Hb measurements:
Results: The most accurate Hb estimation is achieved when monitoring 8× per month (Hberr = 0.23 ± 0.05 g/dl), but it exceeds the accuracy of the measurement device. The estimation error increases to 0.34 ± 0.07 g/dl when monitoring 4× per month, 0.39 ± 0.08 g/dl when monitoring 2× a month, and 0.45 ± 0.09 g/dl when monitoring 1× per month. Estimation error comparable to instrument error information is as follows: 8× per month, 15 patients; 4× per month, 22 patients; 2× per month, 6 patients; 1× per a month, 6 patients.
Conclusions: Four times a month is the clinically optimal Hb monitoring frequency for anemia management.
The accuracy of Hb measurements and adjustment of Iron and EPO requirements is an important adjunct to dialysis therapy tied directly to mortality based on high or low values. I suspect many dialysis units will be tempted to monitor Hb no more than twice a month in otherwise stable patients with the pressure of standard labs included in only one monthly payment for all dialysis services. This is one laboratory of great clinical importance that in my opinion is at risk of the financial managers making decisions based on what is best for the dialysis company instead of what the clinical evidence from this one study suggests is best for the patient. Follow up studies of the impact of the bundle are needed to see how the majority of units respond on Hb management as well as the many other clinical interventions subject to the values of monthly labs.