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Published on: May 16, 2016
Contamination levels in blood samples drawn from the injection intravenous line
Laura L Boles Ponto1, Michael M Graham, John C Richmond
1University of Iowa College of Medicine, Department of Radiology, Division of Nuclear Medicine, Positron Emission Tomography Imaging Center, Iowa City, IA 52242, USA. laura-ponto@uiowa.edu
Purpose:
Securing two intravenous lines, one for injection and one for blood sampling, can be nearly impossible in compromised patients, therefore, a need exists to quantify the potential error when simplified techniques are employed.
Method:
Two venous catheters were placed. 2-deoxy-2-[18F]fluoro-glucose (FDG) was infused through one of the catheters. Venous blood samples were drawn from each line. Triplicate aliquots of plasma were analyzed in duplicate.
Results:
Concentrations from the infusion line were 2.0% higher than the concentrations from the noninfusion line. The average error was 3.3%, 2.0%, and 0.7% higher for the first, second, and third samples, respectively.
Conclusions:
Blood sampling through the infusion catheter is a viable alternative to the placement of separate venous catheters. Sampling from the injection catheter, even with tubing flush and replacement, will potentially incur small (generally < 10%) over-estimations in concentration in initial samples. Subsequent sampling reduces the error to essentially zero by the third sample.

