Prevalence and cost of hemolyzed samples in a large urban emergency department

Sir, The preanalytical phase of the total testing process, including those activities specifically associated with collection of venous blood, is the leading source of errors in laboratory medicine [1]. Spurious hemolysis, which is typically defined as the presence of cell-free hemoglobin in serum or plasma specimens due to in vitro erythrocyte injury, is indeed the leading reason of sample rejection in health care, and across different clinical settings [2]. The frequency of sample hemolysis is particularly high in short stay units such as the emergency department (ED) [3, 4]. This concerning evidence is mainly due to the fact that blood is typically drawn using existing intravenous lines (IV), because this practice avoids to search for another venous access for collecting blood, thus reducing patient discomfort and increasing efficiency during serial sampling. Several lines of evidence attest, however, that erythrocyte injury is commonplace in samples drawn through IV catheters, thus explaining such a high burden of hemolyzed specimens in EDs and intensive care units [5]. Several mechanisms have been advocated to support the notion that red blood cells may be injured during the transit through indwelling lines, including shear stress for collapse of plastic material of IV devices when blood is forced into evacuated blood tubes, the turbulence attributable to gaps of pressures between veins, catheter device, and evacuated collection tubes, as well as the presence of unidirectional valves within the catheter [6]. Although a large number of studies have assessed the prevalence of this problem [5, 6], no reliable data have been provided about the economical burden (including cost of material and personnel) of this common preanalytical issue to the best of our knowledge. This retrospective study was settled in the large urban ED of the Academic Hospital of Parma (Italy), which serves a facility with 1300 beds and specialized wards and accounts approximately 90 000 accesses per year. Upon ED admission, an IV catheter is placed in all patients that are likely to require infusion therapy or serial testing such as in the case of those with suspected acute coronary syndrome or needing therapeutic drug monitoring. In these patients, the diagnostic samples (Vacutainer SST II Plus serum tubes; Becton Dickinson Italia, Milan, Italy) are typically collected by catheters (1.0 9 3.2 mm, 20-gauge catheter; Neo DELTA VEN, Viadana, MN, Italy), whereas straight needle venipuncture (21-gauge; Becton Dickinson Italia) is used for drawing blood in the remaining cases. The statistics about modality of blood drawing (i.e., from caterers or straight needles) and number of serum samples referred from the ED to the central laboratory was based according to data of year 2012, retrieved from the hospital database and from the central laboratory information system (LIS). The prevalence of unsuitable samples throughout the same study period, thus including hemolyzed specimens (i.e., those containing a cell-free hemoglobin ≥0.5 g/L, photometrically assessed on Beckman Coulter DxC, Beckman Coulter, Brea CA, USA), was retrieved from a preanalytical errors recording software, which has been specifically developed for this aim [7]. We have also estimated that the current cost (i.e., for year 2013) of a standard serum tube in our institution is 0.46 €, the average cost per minute of a specialized nurse in our country is 0.021 €/min, and the mean time needed for collecting a blood specimen in our ED is 2.57 min. A total of 166 414 diagnostic serum samples were drawn in the ED throughout the 12-month-observation period, 129 803 (78%) of which were collected through IV catheters. The rates of hemolyzed specimens collected from catheters and straight needle venipuncture were 29% and 1%, respectively. According to these figures, hemolysis in specimens collected from catheter was associated with recollection of 37 643 samples, whereas hemolysis from straight needle venipuncture was associated with recollection of 366 samples, respectively. The overall cost of serum samples collection in the ED throughout the study period was 85 532 € (76 550 € for material and 8981 € for personnel, respectively). According to data of sample rejection, the overall economical burden attributable to recollection of specimens in the ED was 19 535 € (17 484 € for material and 2051 € for personnel, respectively), thus accounting for 22.8% of