Common problems in the use of serum - Database & Sql Blog Articles

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1. How to store and thaw serum without impairing product quality?

Once the serum is removed from the freezer, it should be placed in a refrigerator at 2–8°C to slowly thaw. After complete thawing, allow it to reach room temperature. It’s important to gently shake the serum periodically during the thawing process to ensure even mixing and prevent localized concentration or precipitation.

If stored at 2–8°C for extended periods, certain proteins and lipoproteins (such as cold agglutinins, fibrinogen, and lipoproteins) may form visible precipitates or cause cloudiness. To maintain optimal quality, it's recommended to store the serum at -20°C or lower and avoid repeated freeze-thaw cycles. If only part of the serum will be used, it should be aseptically transferred into a sterile container and returned to the freezer promptly.

2. What are the flocculent precipitates in serum, and how should they be handled?

The precipitate typically consists of fibrin and lipoproteins, which are natural components of serum and do not affect its usability. To remove them, you can centrifuge the serum at 400g for 1–2 minutes. Alternatively, let the serum sit undisturbed, then carefully transfer the supernatant to a new sterile vial. Filtration is generally not recommended, as the precipitate may clog the filter and reduce efficiency.

In most cases, shaking the serum gently and warming it to 37°C will help dissolve the precipitate. When using the serum, it’s best to shake it thoroughly and warm it to 37°C before use. This ensures that any sediment dissolves naturally and does not interfere with your application.

3. How to prevent precipitation in serum?

To minimize the formation of precipitates, follow these guidelines:

• Thawing: Shake the serum regularly during the thawing process to ensure even temperature distribution and prevent localized concentration.
• Cryopreservation: Periodically shake the serum while storing it at low temperatures to maintain uniform composition and avoid sedimentation.
• Temperature control: Avoid rapid temperature changes, such as directly thawing from -20°C to 37°C. Sudden shifts can cause protein denaturation and precipitation.
• Heat exposure: Do not leave the serum at 37°C for too long, as this can lead to cloudiness and degradation of sensitive components.
• Heat inactivation: This step is often unnecessary unless required by your protocol. If performed, it should be done at 56°C for 30 minutes, with constant gentle shaking to prevent excessive sediment formation.

By following these steps, you can maintain the integrity and performance of your serum for optimal experimental results.