Sample Collection Procedure

Pre‑Collection Requirements

• Blood samples must be collected after a fasting period of 10–12 hours. (Non‑fasting samples may affect test outcomes and lead to lipemia.)
• The donor must refrain from alcohol consumption for at least 48 hours prior to sampling.

Blood Collection Process

• Blood must be drawn by trained professionals using appropriate equipment and standardized techniques.
• Samples should be collected into either red‑cap plain tubes or yellow‑cap gel biochemistry tubes.
• (For trace element analyses, the appropriate specialized tube must be used.)
• After collection, the tube must be allowed to stand upright for 30–40 minutes.
• (The waiting period must not exceed 60 minutes. Adhering to these times prevents erythrocyte lysis and hemolysis.)
• At the end of the waiting period, samples must be centrifuged at 3000 rpm for 10 minutes.
• Centrifugation will separate red blood cells to the bottom and form a serum layer on top.
• On average, 60% of the collected whole blood volume will yield usable serum.
• Serum must be transferred into Eppendorf tubes using a pipette.
• To ensure workflow efficiency and prevent misidentification, Eppendorf tubes must be labeled with sequential numbers placed on the tube cap and the textured side surface.
• Example: 1, 2, 3 … 249, 250

Sample Storage

• Serum samples in tightly closed Eppendorf tubes can be stored at –80°C for up to 12 months.
• (Certain tests may have different storage requirements.)
• Freshly obtained serum may be kept at +4°C for up to 48 hours, depending on test specifications.

Sample Transfer

• Samples should be transported from Point A to Point B using dry ice (–78.5°C), which is the standard method utilized by our organization.
• If the samples are not frozen, they must be transported at +4°C.

Tubes to Be Used

• Red‑cap or yellow‑cap (gel) biochemistry tubes are required for standard serum collection.

Critical Handling Notes

• Numbering must not be written on tube labels; labels may detach during transit.
• Samples must be placed sequentially into transport containers and securely closed to prevent accidental opening.
• To avoid confusion, numbers 6 and 9 must be underlined.
• A sample list must be provided along with all specimens.
• Tissue samples must be placed in Eppendorf tubes or wrapped airtight and stored at –80°C.
• Tissues must never be stored in formaldehyde.

Factors Leading to Hemolysis

• Prolonged tourniquet application.
• Incomplete centrifugation.
• Allowing whole blood to stand for more than 2 hours before serum separation.
• Drawing blood from hematoma‑affected areas.
• Using syringes with rapid aspiration, forceful mixing, or rapid injection into tubes.
• (Syringe use should be avoided unless strictly necessary.)
• Exposure to cooling or heating cycles.

Tissue Samples

• After collection, tissues must not be placed in any solution.
• The sample should be wrapped in aluminum foil, placed in an Eppendorf tube, and stored at –80°C.

HbA1c Testing

• Must be performed in whole blood.
• Blood must be collected into an EDTA tube (purple cap) and stored at +4°C.
• The sample must not be frozen.

Milk Samples

• Must be stored at –80°C immediately after collection.
• A minimum of 5 mL, ideally 10 mL, is required for optimal filtration and analysis.

Complete Blood Count (CBC / Hemogram)

• Must be performed in whole blood.
• Blood must be collected into an EDTA tube (purple cap) and stored at +4°C.
• Samples must not be frozen and should be dispatched without delay.

Recommended Blood Collection Tube Brands

• BD
• Greiner