title: Determining optimum hemoglobin sampling for anemia management from every-treatment data.
abstract: OBJECTIVE
  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.
  
  
  METHODS
  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; 8×, 4×, 2×, or 1× 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 8× per month (Hb(err) = 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.
authors.affiliation: University of Louisville, Department of Medicine, Louisville, KY 40202, USA. adam.gaweda@louisville.edu
authors.forename: Adam E
authors.initials: AE
authors.lastname: Gaweda
authors.forename: Brian H
authors.initials: BH
authors.lastname: Nathanson
authors.forename: Alfred A
authors.initials: AA
authors.lastname: Jacobs
authors.forename: George R
authors.initials: GR
authors.lastname: Aronoff
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Germain
authors.forename: Michael E
authors.initials: ME
authors.lastname: Brier
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D000740:Anemia / Q000097:blood / Q000188:drug therapy* / Q000209:etiology; D015415:Biomarkers / Q000097:blood; D001800:Blood Specimen Collection; D018849:Controlled Clinical Trials as Topic; D016903:Drug Monitoring / Q000379:methods*; D005260:Female; D005583:Fourier Analysis; D006397:Hematinics / Q000627:therapeutic use*; D006400:Hematocrit; D006454:Hemoglobins / Q000378:metabolism*; D006801:Humans; D007676:Kidney Failure, Chronic / Q000097:blood / Q000150:complications / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D011237:Predictive Value of Tests; D011446:Prospective Studies; D006435:Renal Dialysis; D015203:Reproducibility of Results; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D015415:Biomarkers; D006397:Hematinics; D006454:Hemoglobins