Transillumination: a new tool to eliminate the impact of venous stasis during the procedure for the collection of diagnostic blood specimens for routine haematological testing

Introduction: The collection of diagnostic blood specimens for routine haematological testing (RHT) is traditionally performed with tourniquet. However, the transillumination devices based on cold near-infrared LEDs have been formerly proposed as a valuable tool for identifying reliable venous accesses, especially in patients with difficult or small veins, such as children. This study was aimed to evaluate whether a transillumination device can advantageously replace the use of the tourniquet during the procedure for collection of blood specimens for RHT and thereby eliminating the discomfort and risk of spurious results caused by excessive or prolonged venous stasis. Methods: Two hundred and fifty volunteers were divided into five groups (G1, G2, G3, G4 and G5) to compare the results of RHT between blood sample collected with transilluminator device (left arm) and with tourniquet application (right arm) for 30 s(G1), 60 s(G2), 90 s(G3), 120 s(G4) and 180 s(G5). Results: No significant increases were observed in any of the haematological parameters tested in G1 when compared with blood collected by the transilluminator device. From G2 to G5, significant increases were observed for the platelet count, red blood cell count, haemoglobin, haematocrit, white blood cell count, neutrophils, monocytes and eosinophils. From G3-G5, further increases were observed for lymphocytes. Clinically significant variations were, however, observed for basophils in G2; red blood cell count, haemoglobin, haematocrit and basophils in G3 and eosinophils in G3 only. Conclusion: As such, considering that inappropriate use of the tourniquet is commonplace, we conclude that transillumination devices can represent a suitable tool to eliminate the venous stasis and to improve the quality of phlebotomy procedures.