Production cost of autologous platelet rich plasma gel*

Objective: to estimate the direct cost of producing autologous platelet rich plasma gel. Method: an economic, prospective, longitudinal study with direct cost estimation, from the perspective of the Unified Health System, conducted in a university hospital in the state of Rio de Janeiro, over a period of 12 weeks. It was approved by the Ethics Committee of the School of Medicine. Direct observation of 18 participants was conducted. Material and human resources categories were analyzed for production costs. Results: the cost of producing platelet rich plasma gel was US $4.88 per session, for a total of US $5.16, when the material resources per unit were considered in the Unified Health System. The time to complete the procedure was approximately 22 minutes. Conclusion: the production of platelet rich plasma gel involves low cost material resources for both blood collection and preparation, enabling universal access to treatment. The procedure requires trained staff in an appropriate location; it is a safe and inexpensive technology.


Introduction
Platelet rich plasma (PRP) is considered a promising technology in topical therapy, as it contributes to the wound healing process. The mechanism of action is related to the actions of: biomolecules, such as adhesive proteins, which promote cell interaction, hemostasis, coagulation and extracellular matrix composition; coagulation factors and associated proteins that produce thrombin; fibrinolytic factors and associated proteins that produce plasmin and vascular remodeling; and, proteases and antiproteases, which act on angiogenesis, vascular remodeling and coagulation control. Growth factors promote chemotaxis, cell proliferation and differentiation, and angiogenesis; chemokines, cytokines and others act to regulate angiogenesis and intracellular communication; and, antimicrobial proteins have bactericidal and fungicidal actions (1) .
Thus, the PRP acts in the various healing phases, promoting the shortening of the inflammatory phase by means of hemostasis, the provisional fibrin matrix, and the reduction of biofilm, promoting the formation of granulation tissue (chemotaxis, angiogenesis, and cell proliferation), epithelialization, keratinocyte proliferation and migration, and remodeling, with extracellular matrix synthesis (1) .
Platelet rich plasma is a product that originates from the centrifugation of whole blood, which is rich in growth factors and structural proteins that stimulate collagen and the extracellular matrix production that promote tissue repair, and which stimulate neovascularization and tissue regeneration (2) . It can be of an autologous nature, when the blood used for centrifugation comes from the patient himself; homologous, when the source is another patient; and heterologous, when it is derived from animal blood.
The effectiveness of autologous, heterologous, and homologous PRP requires further studies (3) .
Studies performed in humans have shown the effectiveness of topical PRP in stimulating the healing of chronic wounds, such as diabetic ulcers, when compared with other antiseptic dressings for both healing and infection prevention (4) . Studies with venous ulcers have shown improved area reduction and a higher number of healed ulcers (5)(6)(7)(8) .
Platelet rich plasma infiltrations have also been studied in clinical trials, such as: meniscus muscle repair with functional improvement after 18 weeks (9) ; decrease of complications of primary total joint arthroplasty, with diminished bleeding and improved healing (10) ; and, the use in knee osteoarthritis showed improvement of degeneration and quality of life (11) .
Autologous PRP, considered to be a bio stimulant, has also been used in dermatology for facial, neck, and hand rejuvenation due to its ease of application, lower risk of infection and allergies, in addition to its having hemostatic properties that reduce the possibility of bruising (12)(13)(14) . In addition to dermatological treatments, it has been used in areas such as androgenic alopecia in men and women, where it demonstrated an increase in the quantity and caliber of hair (15) . Thus, the use of PRP has grown significantly in topical therapies.
It can be prepared using commercial kits, a more scientific evidence to support its regulation (16) .

Given this, the National Health Surveillance
Agency (ANVISA -Agência Nacional de Vigilância Sanitária) determined, in Technical Note No. 64/2015, that the processing of PRP for autologous purpose is allowed on an experimental basis, and that closed systems used in health facilities should be regulated by ANVISA (17) .

The Federal Council of Dentistry, in Resolution
No. 158, of June 8, 2015, allows venipuncture and manipulation of PRP, in a closed system, by a qualified dentist or a health professional in conjunction with the dentist (18) .
Currently, scientific evidence studies such as  (5,19) . Other studies with economic designs, analyze the cost of kits available at a mean cost of € 132.90 per kit per PRP session (20) and US $450.00 per two sessions (21) . Both of these studies were conducted outside the Brazilian context, and with a different socioeconomic scenario.
Given the worldwide evidence of PRP use, and the possibility of obtaining and using PRP, this study www.eerp.usp.br/rlae 3 Ribeiro APL, Oliveira BGRB.
aims to contribute with evidence on the cost of human resources, specifically nurses, in obtaining blood and preparing the PRP.
Resource allocation effectiveness has been the subject of policy discussions, as with health spending growth and limited resources; decision-making on resource allocation should be based on health technology assessment, as the health economy is based on opportunity cost, that is, resources applied to certain programs and technologies imply that others are not provided, so that their cost is not only represented by the resources spent on that technology, but also on the value of what is no longer being provided (22) . In this sense, cost analyses and economic assessments can provide decision-making inputs, contributing significantly to health policies (23) .
Cost analyses are the key steps in providing support for the development of economic assessments (24) , which involve comparing the cost between one or more alternatives, and the outcomes of interventions.
The objectives were to estimate the direct cost of producing autologous PRP gel, and to compare the cost of PRP production, considering the material cost in units of the Unified Health System (SUS).

Method
This was an economic, prospective, longitudinal study, with direct cost estimation, whose setting was the SUS, conducted in a university hospital in the state of Rio de Janeiro, over a period of 12 weeks.
Direct costs are related to the resources consumed directly in treatment, health intervention, or care, such as: material and human resources, products, and services (22) .
This study is part of a macroproject, "Effectiveness For production of autologous PRP gel, two steps were necessary: Step 1 -participant's blood collection by venipuncture, with vacuum catheter; Step 2 -blood centrifugation to prepare the PRP by means of an adapted single centrifugation technique (25) and activation using 10% calcium glyconate in the PRP gel.
To estimate the direct cost of production, the following categories were analyzed: material and human resources.

Data collection was performed from May of 2016 to
December of 2017, using direct observation to identify and quantify the cost items (material resources) required to perform the procedure. The length of time required to perform the procedure was timed. The human resources assessed were nurses who had been trained to perform the procedure for at least one year.
For the production of the PRP gel, a fixed angle bench centrifuge with a capacity of 12 tubes (conical bottom) of 15 ml, with an adjustable speed of up to 4000 rpm, and a timer of 1 -60 minutes was used.
For each session, the material resources and the minimum quantity required to perform the procedure are described in Figure 1.

Material resources for production of autologous platelet rich plasma gel
Step   Step Cost category

Results
The Step 1 cost, in dollars per day per participant was US $1.23. The human resources and material resources category showed equivalent costs, as it is a procedure that does not require much time to perform.
The mean time in minutes for blood collection was 4.0 ± 0.8 minutes. Still, the cost of the human resources category was slightly higher, representing 54.2% of the total cost (Table 1).

Discussion
The PRP production method is considered to be simple, although it requires a speed-regulating centrifuge, and training for careful handling (2) .
The PRP gel production in this study was autologous, using single centrifugation for topical use. There are several methods and processes for converting whole blood into a product (PRP) for topical application; all include blood centrifuging. Differences in the centrifugation process include velocity, acceleration, deceleration, angulation, and radius, as well as the types of platelet lysis activators that can be: calcium chloride with or without thrombin, batroxobin (a proteolytic enzyme that acts on plasma coagulation), thrombin, and freezing (26) .
Autologous PRP has high therapeutic potential and can be used in various formulations and in various fields of medicine and bioengineering. In 2012, more than 40 autologous platelet products were already available, with different characteristics in relation to platelet enrichment, presence of leukocytes, activator type, and final volume, making it difficult to compare results between studies (27) .
The closed system PRP preparation kit with centrifuge and preparation material for up to 100 PRP ranges from US $811.35 to US $929.95, on the market.
Commercialized systems enable the fractionation of plasma rich growth factor (PRGF-Endoret), where the vacuum suction is controlled in the fractionation tube.
After separation of the PRP occurs, calcium chloride for platelet activation (28) , or ascorbic acid, thrombin and calcium chloride are added to centrifuged plasma for lysis and activation of PRP (Autologel™) (28) . to 20 minutes, and the costs ranged from 400.00 to 1600.00 RM (29) . The cost of the human resource involved for preparation and the cost of the centrifuge was not evaluated in this study.
Another study, conducted in the United States, shows that it is possible to train professionals to obtain PRP, via a single centrifuge cycle at 3200 RPM (1430G), for 10 minutes, with a material cost of less than US $10, with a similar time as is suggested by commercial kit manufacturers (30) . In these studies, although the cost of human resources and the centrifuge has not been accounted for, it is clear that the preparation of PRP without the commercial kit reduces the cost, enabling it to be used in the different types of treatment in which PRP has been shown to be effective, including within the SUS.
Moreover, a barrier remains for comparing cost studies, because many studies use materials and methods that are used with commercial kits, which increases the cost of materials and restricts treatment in the public system (30) . Regarding the procedure, it is important to consider that competence in performing the procedure directly influences the cost of a product. Training is an important step, and should be performed by competent professionals, generating an interface of inter-professional education.
This is especially true when it is observed that the cost of human resources is higher than the cost of material in the development of processes and products.
In this study, human resources accounted for 85.8% of the total cost of one PRP session per participant. In other studies, the cost of human resources represented the largest percentage of the cost of outpatient procedures, such as the treatment of venous ulcers with Carboxymethylcellulose gel (31) and compressive therapy (32) . improving processes, care models and protocols, aimed at customer care and Administrative Technology, with management of operational processes which require knowledge and skills; using indicators, administrative processes, and cost management in care (33) .
Nurses are the professionals who have incorporated the practice of care the most, and their professional development has been permeated by the acquisition of fundamental theoretical and philosophical bases, incorporating technological innovations without losing the values, vision, and mission of their profession which means "giving attention to", treating, respecting, and welcoming the human being and his/her needs". Thus, the professional advancement of nurses is important, considering that this is a human resource which is committed to the sustainability of the health system (34) .
The lack of studies on the cost of PRP production conducted in the Brazilian context that could be used to compare the findings of this research was a limitation of this study.

Conclusion
The cost of producing autologous PRP gel for topical use involves low-cost material resources for blood collection and blood centrifugation, totaling US $4.88 per session, and US $29.31 ± 1.63, for a six-session protocol, considering the nurse as the human resource.