Impact of experimental hypercalcemia on routine haemostasis testing

Abstract

BackgroundThe blood to anticoagulant ratio is standardized according to the physiological calcium concentration in blood samples conventionally used for hemostasis testing. Specifically, one fixed volume of 0.109 mmol/L sodium citrate is added to 9 volumes of blood. Since little is known about the impact of hypercalcemia on the calcium-binding capacity of citrate, this study was planned to investigate the effect of experimental hypercalcemia on routine hemostasis testing.MethodsFifteen pooled citrated plasmas with matching lithium-heparin pooled plasma from patients with different values of prothrombin time (PT) were divided in three aliquots of 0.6mL each. The first paired aliquots of both citrate and lithium-heparin plasma were supplemented with 60μL of saline, the second paired aliquots with 30μL of saline and 30μL of calcium chloride and the third paired aliquots with 60μL of calcium chloride. Total and ionized calcium was measured in all aliquots of citrate and lithium-heparin plasma, whereas PT, activated partial thromboplastin time (APTT) and fibrinogen were measured in citrate plasma aliquots.ResultsTotal calcium concentration gradually increased in both lithium-heparin and citrate plasma aliquots 2 and 3 compared to baseline aliquot 1. The concentration of ionized calcium also gradually increased in lithium-heparin plasma aliquots 2 and 3, whereas it remained immeasurable (i.e., <0.10 mmol/L) in all citrate plasma aliquots. No significant differences were observed for values of PT, APTT and fibrinogen in citrate plasma aliquots 2 and 3 compared to the baseline aliquot 1, with a mean bias was always comprised within the desirable quality specifications derived from biological variability data.ConclusionHypercalcemia, up to severe hypercalcemia does not generate significant bias in results of first-line coagulations tests, so that hypothetical consideration of adjusting citrate-blood ratio is unjustified in hypercalcemic patients.

Comparison of Commercially Available Blood Collection Tubes Containing Sodium Citrate and Hirudin in Platelet Aggregation Testing

“…The clinical applications of platelet reactivity testing has put a focus on development of novel strategies for platelet reactivity assessment [ 14 ]. But with the development of new and improved hemostatic assessment methods, the issue of the correct pre-analytical conditions, such as which anticoagulant and concentration to use, has been receiving increased attention from researchers [ 7 – 10 , 15 ]. Thus, the aim of our study was to clarify some of the issues regarding anticoagulant use in LTA.…”

Comparison of catheter thrombogenicity in a modified chandler loop model using goat blood

“…18 However, we believe the impact of the citrate and subsequent recalcification on heparin activity was minimal. As long as sufficient calcium is returned to the sample there is minimal impact on the ability of blood to clot in routine clotting assays, 19 and use of recalcified blood in combination with other anticoagulants in a Chandler loop-like model has been previously reported. 7 The ability to recalcify samples with calcium chloride to reverse the effects of citrate and permit coagulation to occur was important in this study as it permitted the use of multiple heparin concentrations with a single blood sample and allowed for the precise control of the time of coagulation initiation.…”

Preanalytical issues that may cause misdiagnosis in haemophilia and von Willebrand disease

“…Perhaps less well known/frequent, are effects of over‐filling evacuated blood tubes (especially as available volumes facilitating over‐filling are minimal for most blood tubes). The most likely effect here is to compromise adequate mixing of blood, potentially leading to sample clotting—either complete or partial …”