Impact of water temperature on reconstitution of quality controls for routine hemostasis testing

BACKGROUND: This study aimed to investigate whether the temperature of distilled water used for reconstituting lyophilized routine internal quality control (IQC) material may influence the process of validation of analytical sessions of routine hemostasis testing.

METHODS: Routine hemostasis testing was performed for 10 consecutive days using two levels of IQC materials dissolved using distilled water at three different temperatures (2-4°C, 22-24°C and 36-38°C). The tests assayed comprised prothrombin time (PT), activated partial thromboplastin time (APTT), fibrinogen (FBG), antithrombin (AT), protein C (PC), protein S (PS) and D-dimer (D-Dimer HS 500), using the same ACL TOP 700 hemostasis instrument.

RESULTS: Overall, 50% (i.e. 7/14) IQC measurements displayed statistically significant bias when lyophilized material was dissolved with distilled water at 3-5°C compared to 22-24°C, and in two instances (level I for both PT and D-dimer) the bias was higher than the quality specifications. Concerning lyophilized material dissolved with distilled water at 36-38°C, 21% (3/14) IQC values displayed a statistically significant bias compared to 22-24°C, and in one instance (level 2 for PT) the bias was higher than the quality specifications.

CONCLUSIONS: The results of this study show that water temperature, as used to dissolve lyophilized IQC material, may represent an important pre-analytical variable in routine hemostasis testing, especially cold temperatures. Laboratory professionals are encouraged to standardize water temperature, preferably between 22 and 24°C, before reconstituting lyophilized IQC materials used to validate routine hemostasis testing.