Assessment of a two-needle technique for the measurement of recirculation during hemodialysis.

The definitive measurement of recirculation in a hemodialysis vascular access for hemodialysis requires a peripheral vein blood sample. A two-needle method that avoids this venipuncture by using an "arterial" line sample from the access under low-flow conditions has been recommended. However, this technique has never been assessed in patients with significant levels of recirculation. We compared this low-flow arterial (LFA) technique to the standard method of measuring recirculation in 15 consecutive patients with more than 15% recirculation (mean, 27.6%). We found that recirculation by this two-needle technique averaged 15.2% and that the technique was insufficiently sensitive to be of value in clinical practice.