Use of a conical glass tube in preparation of platelet-rich fibrin is a good way to produce consistent, high-yielding clots at low cost

Platelet rich fibrin (PRF) is a second-generation platelet biomaterial, produced first by Choukran et al.,^[1] by centrifugation of whole blood without adding an anticoagulant, hence considered a fully autologous product. PRF as a biomaterial has gained immense importance in dermatology, particularly in the treatment of non-healing ulcers and wounds.

PRF has a dense fibrin network containing leukocytes, cytokines, growth factors such as platelet-derived growth factor and vascular endothelial growth factor, and glycoproteins like thrombospondin-1.^[2] Their optimum production and release depend solely on the correct method of preparation with correct instrumentation.

Preparation of PRF has been attempted using a variety of methods and different apparatuses. Vacutainers, plastic conical tubes, and small blood collection tubes have all been used for the preparation of PRF clot lately.

Silica-coated blood collection sample tubes have also been used, but only 5ml of blood can be accommodated in a tube, giving a suboptimal yield of clot. Using multiple tubes increases the cost of therapy multifold.

The use of plastic centrifuge tubes or vacutainers for preparing PRF clot is not desirable, as there is little to no fibrin polymerization due to the absence of the clot activator silica. The end result is a weak clot formation or even the absence of a clot, after a variable period of time following centrifugation. Since the clot, if formed, is not immediate, the released cytokines fail to get entrapped inside the fibrin mesh and are used up prematurely or discharged in the serum, defeating the purpose of PRF clot preparation.^[3,4]

Use of a 15 ml conical glass tube [Figure 1] for preparation of PRF clot solves the abovementioned problems. The glass tube contains silica, which is a potent activator of blood. When the blood comes in contact with silica, there is slow and controlled polymerization of fibrinogen to fibrin, which creates a favorable and physiological architecture of the final product, the PRF clot.

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Figure 1:

A 15 ml conical glass tube used for the preparation of PRF. PRF: Platelet rich fibrin

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This natural polymerization results in increased incorporation of circulating cytokines within fibrin mesh, which are released slowly, creating a long-term effect. This dense and natural fibrin also protects the cytokines from proteolysis.

A conical glass centrifuge tube can be used for preparing the PRF clot using the following method. After obtaining informed consent, a 15 ml blood sample is drawn from the antecubital vein of the patient’s arm, which is quickly collected in the tube. The tube is immediately placed in a centrifuge, balanced, and spun at 3000 rpm for 10 minutes at room temperature. After centrifugation, a strong PRF clot is formed immediately [Figure 2], which is separated from the tethered RBCs and is ready for use [Figure 3].

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Figure 2:

Formation of PRF clot inside the tube immediately after centrifugation. PRF: Platelet rich fibrin.

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Figure 3:

Healthy PRF clot after being removed from the tube. PRF: Platelet rich fibrin.

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This tube is also reusable, further reducing the cost per treatment. Cleaning the tube after use, followed by dry heating,boiling, or dipping the tube in 2.4% glutaraldehyde solution for 10 hours at room temperature(preferred method), ensures its sterility.^[5] Rinsing the tube with distilled water or normal saline thereafter makes it ready for reuse.

A 15 ml conical glass tube is reusable, requires minimal maintenance, and produces a good yield of strong and firm clot immediately after centrifugation. The results are reproducible at a minimum cost, hence a good solution for the problems encountered in the preparation of PRF by other methods.