Studies on the quality of specimens obtained by skin-puncture of children. 2. An analysis of blood-collecting practices in a pediatric hospital.

We quantified blood-collecting practices for chemistry in a pediatric hospital. Skin-puncture provided 67% of samples, and in-dwelling catheters (lines), 31%. About 46% of samples collected (day-shift) were urgent ("stats"). A single skin-puncture provided 448 microL (range, 150-1350) of blood, and 80% of requests, but only 58% of stats. About 1.3 punctures per request were required. Time spent collecting blood was 11.0 min per single request. Patients undergoing total parenteral nutrition took 17.9 min and 3.6 skin-punctures per request. Analytical time for stat blood gases was about 6 min, total ("turnaround") time, about 16 min. Turnaround time for stat requests involving the Ektachem 400TM instrument was 32.4 min; for non-stat, at least 56 min. Other tests required 151 min. Blood gases and electrolytes represented the majority of all tests ordered, and 97% of in-dwelling line blood-draws. There was no correlation between age and number of tests per request, but the youngest patients (0 to 1 year) had more skin-punctures per request (1.4), along with the greatest number (55.5%) and frequency of tests.