Comparison of the Single-Syringe Push-Pull Technique With the Discard Technique for Obtaining Blood Samples From Pediatric Central Venous Access Devices

The discard technique is the most widely used method of obtaining blood samples from patients with central venous access devices (CVADs), but risks removing more blood than is necessary for laboratory testing and may increase a patient's risk of anemia. We hypothesized that laboratory results from pediatric blood specimens obtained via CVAD using the single-syringe push-pull (formerly called the mixing) method and the discard method would be similar. Blood samples were obtained from pediatric oncology patients in a hospital setting using both collection methods and laboratory values were analyzed for concordance using the pairwise t-test, intraclass correlation coefficient, and Bland-Altman analysis methods. Statistical analysis revealed significant differences for sodium, potassium, chloride, bicarbonate, creatinine, calcium, white blood cell count, hemoglobin, hematocrit, and platelet count, but these differences were not clinically significant and within the standard error of measurement for the instrument. Given the similarity in laboratory results, the push-pull method should be considered for obtaining blood samples from CVADs in pediatric patients to avoid unnecessary blood loss.