有文献指出，扎止血带1分钟以内，血液标本中各项检验指标不会发生变化，但时间超过3分钟或止血带捆扎过紧，会造成血流阻滞，引发溶血、血小板激活、纤溶系统激活等，可使检验项目的结果产生偏差，甚至诱导误诊。
Some literatures have pointed out that within one minute of tourniquet binding, all test indexes in blood samples will not change, but if the time is more than three minutes or the tourniquet binding is too tight, it will cause blood flow block, cause hemolysis, platelet activation, fibrinolysis system activation, etc., which can cause deviation of test items and even lead to misdiagnosis.
从人文关怀的角度来讲，止血带扎的过紧或时间过长，会增加患者的痛苦；一些老年人血管弹性差，还会造成毛细血管破裂，出现皮下瘀血。
From the perspective of humanistic care, too tight or too long time of tourniquet binding will increase the sufferings of patients; some old people have poor elasticity of blood vessels, which will cause capillary rupture and subcutaneous ecchymosis.
因此，抽血时应尽量缩短扎止血带时间。进针后，若血管充盈，应立即松开止血带，接上采血管，血流不通畅可适当调整针头；若血管充盈不好，可视情况扎着止血带，但应尽量控制在1分钟以内。
Therefore, the tourniquet time should be shortened as much as possible. After inserting the needle, if the blood vessel is full, immediately loosen the tourniquet, connect the blood collection vessel, and properly adjust the needle head if the blood flow is blocked; if the blood vessel is not well filled, tie the tourniquet as the case may be, but try to control it within 1 minute.
这些特殊项目要注意：血脂项目、凝血项目、血常规项目抽血时，止血带使用将对化验结果产生较大影响,务必控制使用时间。不应鼓励患者反复握拳，若第一次穿刺不成功，重新采血尽量在对侧。
These special items should be noted: when taking blood from blood lipid items, coagulation items and blood routine items, the use of tourniquet will have a great impact on the test results, so it is necessary to control the use time. The patient should not be encouraged to clench his fist repeatedly. If the first puncture is not successful, take blood again on the opposite side as much as possible.