Which blood specimen from patient will take long to clot?

A blood specimen collected in a tube containing an anticoagulant, such as EDTA or citrate, will take longer to clot because these substances prevent the coagulation process by binding calcium or inhibiting clotting factors. Additionally, blood collected in a glass tube may also take longer to clot compared to plastic tubes due to the smooth surface of glass, which is less conducive to platelet activation.