A Comparison of Coagulation Study Results Between Heparinized Peripherally Inserted Central Catheters and Venipunctures

Purpose/Objective: The purpose of this study was to test an evidence-based procedure of drawing blood samples for coagulation testing from heparinized peripherally inserted central catheter (PICC) by comparing results with blood drawn from venipuncture (VP). Design: A prospective, quasi-experimental design using purposive sampling was used. Setting: The setting was a 230-bed community hospital located in the Southwest. The hospital is part of a 15-hospital system. Sample: The sample was composed of 30 hospitalized patients with heparinized PICCs. Methods: Informed consent was obtained. Using aseptic technique, samples of blood were drawn via VP and from the PICC using the evidence-based procedure. Data were analyzed using Pearson product moment correlations and Bland-Altman analysis. Findings: For 5 coagulation tests studied, correlations between PICC values and VP values ranged from 0.990 to 0.998, indicating almost perfect correlations. In Bland-Altman analyses, mean biases and SDs were small to moderate for prothrombin time, 0.13 seconds (-0.55 to 0.81 seconds) (P = 0.0484); international normalized ratio, 0.010 (-0.050 to 0.070) (P = 0.085); partial thromboplastin time, 2.16 seconds (-5.10 to 9.43 seconds) (P = 0.0033); and fibrinogen, -18.2 mg (-70.4 to 34.1 mg) (P = 0.0033) and 0.52 (-0.73 to 1.77) seconds (P = 0.0003). Correlations of absolute difference versus average ranged from 0.18 to 0.49. Only the paired international normalized ratio samples had P values suggesting nonagreement. Conclusions: Drawing blood samples from heparinized PICCs for coagulation tests using the evidence-based procedure developed for this study resulted in accurate coagulation test results in 4 of the 5 tests: prothrombin time, partial thromboplastin time, and fibrinogen in seconds and in milligrams.