Determining optimum hemoglobin sampling for anemia management from every-treatment data
BACKGROUND AND OBJECTIVES: Anemia management protocols in ESRD call for hemoglobin (Hb) monitoring every 2 to 4 weeks. Short-term Hb variability affects the reliability of Hb measurement and may lead to incorrect dosing of erythropoiesis stimulating agents. We prospectively analyzed short-term Hb variability and quantified the relationship between frequency of Hb monitoring and error in Hb estimation. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: Using the Crit-Line III TQA device, we prospectively observed Hb during each dialysis treatment in 49 ESRD patients and quantified long- and short-term Hb variability. We estimated Hb from data sampled at regular intervals; 8Ã—, 4Ã—, 2Ã—, or 1Ã— per month to establish how well we account for short-term variability at different monitoring intervals. We calculated the Hb estimation error (Hb(err)) as a root mean-squared difference between the observed and estimated Hb and compared it with the measurement error. RESULTS: The most accurate Hb estimation is achieved when monitoring 8Ã— per month (Hb(err) = 0.23 Â± 0.05 g/dl), but it exceeds the accuracy of the measurement device. The estimation error increases to 0.34 Â± 0.07 g/dl when monitoring 4Ã— per month, 0.39 Â± 0.08 g/dl when monitoring 2Ã— a month, and 0.45 Â± 0.09 g/dl when monitoring 1Ã— per month. Estimation error comparable to instrument error information is as follows: 8Ã— per month, 15 patients; 4Ã— per month, 22 patients; 2Ã— per month, 6 patients; 1Ã— per a month, 6 patients. CONCLUSIONS: Four times a month is the clinically optimal Hb monitoring frequency for anemia management.
Gaweda AE, Nathanson BH, Jacobs AA, Aronoff GR, Germain MJ, Brier ME. Determining optimum hemoglobin sampling for anemia management from every-treatment data Clin J Am Soc Nephrol 2010 Nov;5(11):1939-45.