Can blood hemolyze if it sits for 3 days?

Blood Hemolysis After 3 Days of Storage

Yes, blood can hemolyze if it sits for 3 days, but the risk and extent depend critically on storage conditions—properly refrigerated blood at 4°C ± 2°C will maintain integrity for up to 28-35 days, while blood left at room temperature will undergo progressive hemolysis and metabolic deterioration.

Storage Temperature is the Critical Determinant

Proper Refrigerated Storage (4°C ± 2°C)

• Red blood cells stored at the correct core temperature of 4°C ± 2°C maintain their integrity for a maximum of 28 days, which can be extended to 35 days if adenine is added to the storage solution 1
• At 3 days of proper refrigerated storage, red blood cells remain fully viable with minimal hemolysis 1
• Cold chain requirements are essential under European Law to prevent hemolysis and maintain blood component quality 1

Room Temperature Storage

• Blood left at room temperature (approximately 22°C) undergoes progressive metabolic changes similar to those in cold-stored products, but with accelerated deterioration 2
• Recent evidence shows that whole blood stored at room temperature for up to 5 days retains most metabolic and hemostatic function, though this represents non-standard storage 2
• However, once removed from controlled temperature storage, transfusion must be completed within 4 hours to minimize risk of bacterial proliferation and hemolysis 1, 3

The 30-Minute and 4-Hour Rules

Critical Time Limits

• Time outside temperature-controlled environment should be restricted to 30 minutes before blood must either be transfused or discarded 1, 3
• Blood issued cannot be returned to stock if out of a controlled temperature and monitored fridge for longer than 30 minutes 1
• Once removed from refrigeration, the entire transfusion must be completed within 4 hours 1, 3

Evidence Base for These Rules

• A systematic review found that temperature exposure did not adversely affect RBC unit quality or result in significant bacterial contamination in studies examining exposure from 20 minutes to 42 days 4
• The primary concern with the 30-minute rule is bacterial growth, though psychrophilic bacteria that survive refrigeration are unable to begin logarithmic phase growth for several hours after returning to room temperature 5

Hemolysis as a Laboratory Problem

In Vitro Hemolysis

• Hemolysis accounts for over 60% of blood sample rejections in clinical laboratories and is the most common preanalytical error 6
• In vitro hemolysis may occur at all stages of sample collection, transport, handling, and storage 6
• The degree of hemolysis interference depends on the level of hemolysis and the assay methodology being used 6

Clinical Implications

Common Pitfalls to Avoid

• Never assume blood left at room temperature for 3 days is safe for transfusion—this violates all established storage guidelines 1
• Blood components must be visually checked for any leakage, discolouration, or presence of clots or clumps before transfusion 1
• If blood has been outside controlled storage for more than 30 minutes without proper temperature monitoring, it should be discarded rather than returned to stock 1

Proper Handling Protocol

• Blood should be transfused through a 170-200μm filter to remove any potential clots or debris 3
• If blood is issued within a correctly packed and validated transport box, it should be placed back in a blood fridge normally within 2 hours, providing the box is unopened 1
• Transfusion laboratory staff will assess the acceptability of blood for return to stock based on documented temperature exposure 1