Non-vacuum blood collection tubes, also known as "open system" or "manual" blood collection tubes, used in situations where vacuum tubes are not feasible, such as when collecting blood from infants, or in situations where only small volumes of blood are required. They require more manual handling compared to vacuum tubes but serve the purpose of collecting blood samples effectively for diagnostic testing.It hold a capacity ranging from 1 mL to 4 mL endure blood collection without the use of a vacuum for coagulation and diagnostic testing.