Summary Introduction A maximum delay between blood collection and coagulation testing of 4 hours is recommended by most guidelines. As information on optimal storage times is limited, we investigated the potential effect of different storage times of unspun tubes, that is, ≤2, 4, 6, and 8 hours, on routine coagulation test results. Methods Four evacuated polymer tubes containing 0.109 mol/L tri‐Na citrate were drawn from 144 patients, including 39 patients on vitamin K‐antagonists. Except for storage time, all tubes underwent the same preanalytical process. Prothrombin time (PT)/international normalized ratio (INR), activated partial thromboplastin time (aPTT), fibrinogen, factor V (FV), FVIII, and D‐dimer were evaluated in two centers using the same technical conditions. Results Analytical comparison of aPTT, fibrinogen, FV, and FVIII results evaluated after prolonged storage times vs a <2‐hours storage demonstrated significant difference, whereas PT/INR and D‐dimer remained unchanged up to 8 hours. Mean bias between test results obtained after prolonged storage times remained below the desirable values for all studied parameters except for FVIII evaluated after 6‐ and 8‐hours storages, but only in patients with FVIII above 100 IU/dL. Even though the corresponding bias of −5.2% and −8.5%, respectively, remained within the GEHT recommended limits of variation, its evaluation after an 8‐hours storage could lead to significant underestimation of FVIII. Conclusion These results suggest that, in the studied technical conditions, PT/INR, aPTT, fibrinogen, FV, and D‐dimer can be reliably evaluated in tubes stored unspun at room temperature for up to 8 hours after blood collection. That optimal delay should be of 6 hours for FVIII.