Willingness-to-pay threshold for preventing spurious hemolysis during blood sample collection

To the Editor,

Several lines of evidence now attest that spurious hemolysis is the leading source of blood samples’ non-conformance in the vast majority of clinical laboratories worldwide [1], [2]. Some previous studies have attempted to estimate the economic burden of sample hemolysis on healthcare budgets [3], [4], [5], but none of these has provided definitive data on the sustainable economic threshold for implementation of reliable hemolysis prevention tools, to the best of our knowledge. Therefore, we conducted an economic analysis at a large university hospital, aimed at identifying our willingness-to-pay threshold for preventing spurious hemolysis during drawing of blood samples.

The cumulative cost of a blood sample collection at the local facility (i.e. University Hospital of Verona) is 1.358 €, partitioned as follows: 1.047 € for nurse time (i.e. 5 min per venipuncture), 0.155 € for 21-gauge straight needle and holder (Kima Safety, Kima, Padova, Italy), 0.002 € for detergent (Neoxinal Alcolico, Nuova Farmec, Verona, Italy), 0.011 € for gauge pad (Luigi Salvadori, Florence, Italy), 0.006 € for two tube labels and 0.140 € for one clinical chemistry and one coagulation blood tube (Kima, Padova, Italy). This observational study was carried out in accordance with the Declaration of Helsinki and under the terms of all relevant local legislations.

During the entire year 2017, a total number of 782,479 blood tubes were received in the local laboratory for clinical chemistry (n=536,001) and coagulation (n=246,478) testing, of which 10,991 (1.40%) were classified as being significantly hemolyzed according to a local standard operating procedure (SOP) compliant with the International Organization for Standardization (ISO) 15189 document, and based on systematic assessment of serum/plasma indices on both clinical chemistry (Dimension Vista, Siemens Healthcare, Erlangen, Germany) and coagulation (ACL TOP 750, Instrumentation Laboratory, Bedford, MA, USA) analyzers. Sample rejection is set at a value of cell-free hemoglobin >0.5 g/L for potassium and >3.0 g/L for hemostasis testing. Test result suppression for the presence of clinically significant hemolysis is promptly notified to the hospital wards, and a second set of samples is recollected, whenever feasible and necessary.

According to local cost analysis, the overall expenditure for drawing blood for clinical chemistry and coagulation testing was 1,065,458 € during the entire year 2017 at our institution. Overall, recollection of all previously hemolyzed samples would have hence imposed a significant extra economic burden of 14,966 €. By associating this extra and potentially avoidable expenditure with the total number of blood tubes received in the year 2017, we can hence estimate the threshold cost of adopting reliable tools for avoiding sample hemolysis, and thus preventing sample recollection with a new venipuncture, at 0.019 € (i.e. ~2 cents of an €) per single tube in our healthcare facility, which corresponds to 1.4% of the total cost of a routine venipuncture. Whatever preventive measure costing more than this threshold per tube would hence be considered no longer economically viable. It is also worth mentioning here that diagnostic delays due to longer stay in the emergency department (ED) for recollecting blood samples will generate additional expenditures for the healthcare system. Considering that the average cost of the length of stay (LOS) in the ED can be comprised between 1540 and 2200 € per day [6], a 1-h delay for receiving suitable results of laboratory testing would generate an incremental cost of approximately 64–92 € per patient.

Albeit the real value of laboratory diagnostics lies far ahead of a simple balance between cost and profit [7], the results of our analysis show that the economic threshold for implementing reliable hemolysis prevention means [8], thus potentially including specific blood collection sets, needles, holders or even usage of devices allowing rapid hemolysis detection in uncentrifuged blood specimens (e.g. HemCheck, HemCheck Sweden AB, Karlstad, Sweden), is seemingly very narrow (Figure 1), at least in our healthcare facility.

Figure 1:

Willingness-to-pay threshold for preventing spurious hemolysis during blood sample collection related to the overall expenditure of a routine venipuncture.

Nevertheless, this conclusion is exclusively economical, and does not consider either patient inconvenience due to repeated venipuncture or the potential adverse consequences of diagnostic delay caused by the need of recollecting blood samples in urgent healthcare settings, such as EDs or intensive care units, where results of laboratory testing are crucial for managing patients with acute and often life-threatening conditions. This conclusion perhaps applies also to non-hospital laboratories, where the willingness-to-pay threshold may be even higher considering that blood sample recollection in non-hospital facilities is a magnified challenge in terms of turnaround time and delayed diagnosis. Indeed, public tenders for blood collection devices should hence be focused on these essential aspects other than simply relying on lower prices [9].