title: Glucose infusion test: a new screening test for vascular access recirculation.
abstract: BACKGROUND
  Vascular access recirculation is an important cause of diminished dialysis efficiency. We propose a new screening test based on glucose infusion as a tracer for recirculation.
  
  
  METHODS
  The glucose infusion test (GIT) protocol comprises a basal blood sample (A) from the arterial port, a 5 mL bolus of 20% glucose into the venous chamber (time 0), followed by a second sample (B) in four seconds (from 13 to 17 s with QB 300 mL/min) from the same port. The blood glucose level is determined at the bedside on A and B with a reflectance photometer (CV 1.8%). Interpretation of the test is straightforward: If B = A, there is no recirculation, whereas if B > A, recirculation can be calculated from the regression equation: 0.046 x (B - A) + 0.07, obtained from in vitro tests reproducing artificial recirculation at 0, 5, and 10%. To validate this new method in vivo, we compared GIT and the urea test on 39 hemodialysis patients, obtaining a good correlation (r = 0.93). The two tests were considered positive (recirculation present) when the lower 95% confidence intervals were more than zero.
  
  
  RESULTS
  Our patients were divided into two groups: those with (22 out of 39, mean recirculation 11.8%) or without recirculation (17 out of 39, mean 0.06%). The urea test did not recognize 7 out of 22 patients because they had a small recirculation below the urea test limit of detection.
  
  
  CONCLUSIONS
  GIT was more sensitive (detection limit 0.3%), simpler, and immediate in showing the results than the urea test. It is an accurate and low-cost technique for screening and follow-up of vascular access in a dialysis unit.
authors.affiliation: Nephrology Dialysis Unit, Sestri Levante Hospital, Aosta Hospital, Occupational Medicine Unit, and S. Martino Hospital, Genoa, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Magnasco
authors.forename: S
authors.initials: S
authors.lastname: Alloatti
authors.forename: G
authors.initials: G
authors.lastname: Bonfant
authors.forename: F
authors.initials: F
authors.lastname: Copello
authors.forename: P
authors.initials: P
authors.lastname: Solari
mesh_terms: D002408:Catheters, Indwelling / Q000009:adverse effects*; D005947:Glucose / Q000378:metabolism; D006801:Humans; D006435:Renal Dialysis / Q000009:adverse effects*; D014508:Urea / Q000378:metabolism
chemical_list: D014508:Urea; D005947:Glucose