How long can whole blood samples be frozen?

In the fields of molecular diagnostics and research, the duration of cryopreservation for whole blood samples directly affects the quality of RNA extraction and the accuracy of downstream testing. Many users often ask: How long can whole blood be frozen before RNA is extracted?; The answer depends on storage conditions, type of anticoagulant, and extraction method. This article will combine industry data with magnetic bead-based RNA extraction techniques to provide you with professional advice, helping you optimize your sample management process.

A “Safety window period” for whole blood cryopreservation

RNA is highly degradable. If whole blood samples are directly frozen without treatment, the RNA integrity (RIN value) will decrease over time. Studies have shown that:

-20℃ storage: RNA is significantly degraded within 24-48 hours and is only suitable for short-term storage.

-80℃ ultra-low temperature freezing: can be stored for 1-2 weeks (RIN>7), but long-term storage requires the addition of RNA stabilizer (such as PAXgene tube).

Liquid nitrogen quick freezing (-196℃): can be stored for up to several months, but the cost is high, suitable for precious samples.

Key tip: EDTA anticoagulated tubes are more conducive to RNA stability than heparin tubes, avoiding repeated freezing and thawing (each freeze-thaw will degrade RNA by about 15%).

Magnetic bead method of RNA extraction: solving the problem of extracting cryopreserved samples

For frozen whole blood samples, the traditional centrifuge column method is prone to low RNA yield due to incomplete cell lysis. However, the magnetic bead nucleic acid extraction technology has the following advantages and becomes the ideal choice for cryopreserved samples:

1. High tolerance: magnetic beads can be modified on the surface to efficiently bind degraded RNA fragments, and the recovery rate can be guaranteed even if the sample is partially degraded.

2. Automation compatibility: supports 96-well plate high-throughput extraction, reduces operational differences, and is a standardized solution suitable for overseas agents to promote.

3. Strong anti-interference ability: the magnetic bead method is more tolerant to inhibitors such as hemoglobin and heparin than silica gel membrane column, especially suitable for long-term cryopreserved samples.

Suggestions to the purchasing leader: How to choose the kit suitable for the frozen samples?

1. Focus on lysate formulation: the lysis system containing guanidine salt can better inhibit RNase and is suitable for long-term frozen samples.

2. Verify the performance of magnetic beads: select magnetic beads with one uniform particle size and good superparamagnetic properties (such as carboxy-modified magnetic beads) to ensure the consistency between batches.

3. Supporting automation equipment: recommend kits compatible with KingFisher, BioTek and other platforms to improve the purchasing intention of overseas customers.

The cryopreservation time of whole blood samples should be evaluated combined with temperature, anticoagulant and extraction methods. RNA extraction is becoming the industry standard for cryfrozen samples because of its high recovery and stability.

Shanghai Lingjun Biological provides the whole process solution, from the sample preservation tube (such as RNA-Free EDTA tube) to the magnetic bead method kit, to help you easily cope with the demand of overseas market for frozen sample detection.

Supplier

Shanghai Lingjun Biotechnology Co., Ltd. was established in 2016 which is a professional manufacturer of biomagnetic materials and nucleic acid extraction reagents.

We have rich experience in nucleic acid extraction and purification, protein purification, cell separation, chemiluminescence, and other technical fields.

Our products are widely used in many fields, such as medical testing, genetic testing, university research, genetic breeding, and so on. We not only provide products but also can undertake OEM, ODM, and other needs. If you have a related need, please feel free to contact us at sales01@lingjunbio.com.