Note: See the CDC SOP #DSR-052-05, Preparation of Viral Transport Medium, prior to compounding VTM. Be sure to check the CDC website regularly for updates. For more information, see: https://www.cdc.gov/csels/dls/locs/2020/new_sop_for_creating_vtm.html
The test, treat, and track strategy is critical to containing the COVID-19 pandemic, a global health crisis caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The objective of this strategy is to contain the virus by quickly identifying both symptomatic and asymptomatic patients, performing contact tracing, and quarantining patients to reduce transmission.
From the pandemic’s onset, testing has been limited by supply chain problems at all levels. The unprecedented worldwide demand for viral diagnostic testing (ie, polymerase chain reaction [PCR] tests) resulted in critical shortages of key supplies, including flocked nylon swabs for collecting samples and viral transport media (VTM) used for preserving and transporting samples. In response, key companies around the world attempted to quickly scale up manufacturing. These efforts initially stumbled as countries locked down, labor pools fluctuated, and transport systems experienced delays.
In response, the FDA granted emergency use authorizations to allow unapproved medical products (ie, diagnostic tests and related supplies) to enter the market and to relax regulations that allow for expanded production and more timely distribution of already approved products.1 For example, VTM is regulated by the FDA as a medical device because it is used in disease diagnosis. In January 2020, the FDA increased production capacity by allowing manufacturers to sell VTM without submitting a 90-day pre-marketing notification, which includes evidence of equivalence to an existing, legally marketed device. In addition, the FDA issued guidance that temporarily allows Clinical Laboratory Improvement Amendments (CLIA)-certified laboratories to produce VTM for in-house COVID-19 diagnostic testing.2
This article examines the importance of VTM in COVID-19 diagnostic testing and how a department of pharmacy can partner with a hospital laboratory to sustain testing through the manufacturing of VTM.
The Role of VTM in COVID-19 Testing
Viral diagnostic testing consists of three key activities:
Sample collection and transportation is dictated by the type of testing. The most common and reliable COVID-19 diagnostic test is a laboratory-based assay that detects viral nucleic acid through amplification of a SARS-CoV-2 specific sequence, such as reverse transcription PCR (RT-PCR).
SARS-CoV-2 is composed of ribonucleic acid (RNA), which is extremely unstable and degrades easily.3 Thus, storing samples in the wrong environmental conditions can lead to false negative results, as can sample contamination from enzymes or other microorganisms that break down RNA. For this reason, the CDC considers “Proper collection [and storage] of specimens [as] the most important step in the laboratory diagnosis” of COVID-19.2
Sample collection starts with using a sterile swab tipped with a synthetic material (eg, nylon, polyester) to collect secretions from either the patient’s nasopharynx (most common), oropharynx, nasal mid-turbinate, and/or anterior nares (see FIGURE 1). Swabs are ideally “flocked” by electrostatic insertion of pin-like filaments into the swab head, rather than by winding fibers around a shaft, for improved pickup and release of sample. Note that swabs with wooden shafts, cotton tips, and/or containing calcium alginate are not appropriate as they contain genetic material that interferes with diagnostic tests. Only a small subset of available swab inventory is appropriate for viral testing. Collected swabs are then placed in a sterile collection tube and stored at either 2-8°C or -70°C, depending on whether the sample can be tested within 72 hours.2
Within the sterile collection tube is transport media within which the specimen is suspended by breaking the swab at a score point (red line, see FIGURE 2) allowing the head of the swab to fit into the tube. Transport media is designed to be an optimal environment for preserving the viability of a target analyte (ie, virus) during transportation and storage. The gold standard is VTM, also known as universal transport media.2
VTM is preferred as it is a non-hazardous mixture of buffered solutions and antimicrobials that preserves the virus while eliminating contaminant flora that might interfere with testing. It has proven compatibility with a wide variety of clinical tests from PCR to direct antigen testing to culturing, allowing different tests to be run from the same sample.4
Due to VTM shortages, the FDA and CDC have recommended using alternative media, including sterile saline, liquid Amies, and inactivating transport media.2 However, these options do not have the same versatility, stabilizing, and inhibitory properties as VTM. Inactivating transport media is the least desirable as it contains hazardous chemicals that can release toxic cyanide gas when mixed with acids such as bleach, which is a commonly utilized disinfecting agent for eliminating stray contaminant nucleic acids.5,6
Ingredients in VTM
VTM is a device designed to maintain the viability and thus virulence of collected samples. It has been optimized for decades, initially to preserve viability for cultures and later to facilitate nucleic acid-based testing. VTM is composed of fetal bovine serum (FBS), Hanks' Balanced Salt Solution (HBSS), antibiotics and antifungals, as well as phenol red.7 A multitude of variations of the recipe exist and cater to the interactions between sample collection devices (ie, swab) in media solutions, plastic in storage containers, and variability of freeze/thaw cycles.
Ingredients for VTM are commonplace in both clinical and research laboratories. However, within a health-system pharmacy these may be foreign, resulting in concerns from pharmacy colleagues. Thus, the purpose and safety of each ingredient is described below.
Commercially, FBS comes in two forms: heat inactivated and not inactivated. Traditionally, most protocols for making VTM include heat inactivation as a necessary step in preparation. This is to rid the serum of any complement proteins that inadvertently eliminate foreign organisms (eg, viruses). The utility of heat inactivation is debated as some experts consider the complement factors present to be negligible. With lack of definitive evidence, heat inactivation is a conservative approach, especially given the low cost and technical skill needed.
Pharmacy colleagues may be uncomfortable handling FBS as it is a serum-supplement. However, note that FBS does not present any health hazards, physical hazards, or environmental hazards. Additionally, no hazard statements or precautionary statements (ie, prevention, response, storage, disposal) are applicable to FBS.9
See the SIDEBAR for a case study of VTM preparation.
UIHC has been able to meet the increased demand for COVID-19 testing without interruption due in part to the onsite production of VTM. Pharmacy departments, in collaboration with CLIA-certified laboratories, are well-positioned to expedite onsite VTM production when commercial VTM is unavailable. Without onsite VTM production, UIHC’s testing capacity would have been exceeded, resulting in substantial testing delays. As the global supply chain of VTM normalizes, onsite production by pharmacy will no longer be relied upon as a primary source at UIHC. However, in today’s unpredictable world, hospitals must have a back-up plan in place that can be quickly activated and scaled when demand for testing increases and supply chain failures occur.
Felix Lam, PharmD, MBA, BCPS, is the pediatric pharmacy operations manager for University of Iowa Health Care (UIHC) in Iowa City, Iowa. He earned his Doctor of Pharmacy from the University of North Carolina Eshelman School of Pharmacy and his MBA with an emphasis on health care management from the Johns Hopkins Carey Business School while completing a combined PGY1/PGY2 in health-system pharmacy administration at The Johns Hopkins Hospital.
Majd Moubarak, BS, is a pharmacy technician for the University of Iowa Stead Family Children’s Hospital in Iowa City, Iowa. She completed her Bachelor of Science in plant biology from the University of Iowa. When not caring for patients at the hospital, she continues to pursue her research interest in plant regeneration. She is actively pursuing national pharmacy technician certification.
Jonathan Wilson, PharmD, MHA, BCPS, BCSCP, is an adult pharmacy operations manager for the University of Iowa Hospitals and Clinics in Iowa City, Iowa. He earned his Doctor of Pharmacy degree from the University of Minnesota College of Pharmacy. Jonathan completed his MHA at the University of Iowa College of Public Health while completing a combined PGY1/PGY2 in Health-System Pharmacy Administration at the University of Iowa Hospitals and Clinics.
Bradley Ford, MD, PhD, is the medical director of the clinical microbiology laboratory for the University of Iowa Hospital and Clinics. He earned his Doctor of Medicine and Doctor of Philosophy from Stony Brook School of Medicine. His research focuses on optimizing clinical diagnostics using a variety of next-generation microbiology platforms.
Case Study: University of Iowa Health Care
The University of Iowa Health Care (UIHC) is a non-profit, academic medical system that includes 811 beds within two tertiary care hospitals: UI Hospital and Clinics and UI Stead Family Children’s Hospital. Due to the national shortage of viral transport media (VTM), UIHC pursued onsite preparation of VTM for use within the main campus hospitals. In order to meet significant demand (ie, over 500 tests per day), the UIHC pathology department collaborated with the pharmacy department to compound VTM given the availability of primary engineering controls (PECs) within pharmacy and certified pharmacy technicians competent in aseptic manipulations for preparation of sterile products. Furthermore, pathology contributed extensive knowledge of laboratory reagents and VTM validation while pharmacy provided expertise to scale preparation of VTM.
The collaboration resulted in expedited development of procurement and preparation processes to meet the testing demand of the system on short notice. UIHC utilized the CDC and Indiana University Health Clinical Virology Laboratory standard operating procedures on the preparation of VTM to prepare and validate over 2800 units (3 mL aliquots) of VTM within a 1 week time period from project initiation (see FIGURE 4). Validated VTM continues to be used for diagnostic testing of viral infections, including COVID-19.
See the APPENDIX for UIHC’s VTM Master Formulation Record.
The FDA recommends that laboratories certified under CLIA follow the CDC’s standard operating procedure entitled Preparation of Viral Transport Media when compounding and validating VTM during a supply shortage.12 Pharmacy departments collaborating with CLIA-certified laboratories should follow preparation procedures developed utilizing the CDC standard operating procedure prior to laboratory validation of the VTM.
Reagents used in the compounding of VTM may be obtained from a biomedical research supplier or directly from the hospital laboratory in facilities or systems that have this capability. Purchasing reagents from a biomedical research supplier affiliated with your institution provides the benefit of discounted pricing from large volume contracting with vendors. Alternatively, reagents can be purchased directly from a biotechnology reagent producing company serving clinical and research-laboratory clients, and perhaps forsake the benefits of contracted pricing and onsite availability.
Common supplies listed in recipes include serological pipettors/pipet-aids, individually wrapped sterile pipets, sterile conical tubes, filter assemblies, labels, and disinfectants. Supplies can be obtained from a biomedical research supplier or directly from the manufacturer, when not available from hospital inventory or the pathology department.
Equipment & Environmental Controls
Equipment needed to prepare and aliquot VTM is readily available in a laboratory setting (eg, vacuum pump, water bath, refrigerator, incubator, sterile pipette). However, access to an ISO Class 5 environment for preparation and aliquoting of VTM remains a limiting factor for preparation. VTM can be aseptically prepared in a PEC in the pharmacy.
The pathology department assists with quality assurance checks, which include culture-based sterility tests that may be performed in the microbiology laboratory conducting COVID-19 testing. Refer to the CDC Standard Operating Procedure for Sterility and Quality Checks.13
See TABLE 1 for information about expiration dating. The CDC recommends a 1 year expiration date from preparation of VTM bulk product and aliquots while Indiana University Health Clinical Virology Laboratory assigns the bulk product an expiration date of 1 month after first use and aliquots 1 year after preparation.13 The FDA recommends that shelf life, stability, and limitations follow the CDC standard operating procedure guidelines for proper labeling of VTM, in which case VTM is viable up to 1 year after manufacturing.13 UIHC assigned VTM bulk product a conservative 30-day expiration date from the time of preparation. Aliquots received the expiration dating based on the bulk product used for preparation.
Note that USP <797> beyond-use dating does not apply to preparation of VTM as it is a diagnostic device not intended for administration to patients.
See TABLE 2 for information about staffing time required for the steps in VTM preparation.
Master Formulation Record
Official Name: Viral Transport Medium—Fetal Bovine Serum 2%,
Gentamicin 100 µg/mL, Amphotericin B 0.5 µg/mL
**For transport of specimens only**
**Not to be taken internally**
DO NOT FREEZE
Batch Volume: 512 mL
Dispense Product: 3 mL aliquots in conical tubes (~160 units)
Expiration Date for Bulk Product: 30 days (bulk product expiration date given to aliquots)
Storage: Refrigerated, 2-8°C
Description of Ingredients
*Differs from CDC Standard Operating Procedure13
Equipment & Environmental Controls
*Differs from CDC Standard Operating Procedure13
Stock Bottle Label
Method of Preparation
Preparation of Ingredients
a. Heat FBS at 56°C in a water bath for 30 minutes and swirl the bottle every 10 minutes. For accuracy, use a second bottle of similar size as a control and add an equivalent volume of water to the control bottle. Place a thermometer in the control bottle to see when 56°C is reached. Set your timer for 30 minutes at this point13, 14
b. Filter sterilize 500 mL FBS using a 0.45 µm/500 mL filter assembly and laboratory vacuum pump
c. Expiration: 30 days, refrigerated (see Expiration Dating)
a. Using aseptic technique in a non-hazardous BSC
b. All materials shall be sprayed down with alcohol before entering the BSC
c. Reconstitute amphotericin B 50 mg vial to create a 5,000 µg/mL solution
d. Combine 8 mL of amphotericin B 5000 µg/mL with 92 mL of sterile water in a 250 mL sterile, empty IV bag to yield amphotericin B 400 µg/mL
e. Combine 31.25 mL of amphotericin B 400 µg/mL with 62.5 mL of gentamicin sulfate 80 mg/2 mL, then QS with sterile water to 100 mL using another 250 mL sterile, empty IV bag
Preparation of Bulk VTM and Aliquots
Use aseptic technique in a non-hazardous BSC.
All materials shall be sprayed down with alcohol before entering the BSC.
Final Product Description: Pink Solution
Enter our Sweepstakes now for your chance to win the following prizes:
Just answer the following quick question for your chance to win:
Entries are limited to one entry per person in any active sweepstakes.
Thank you for your entry.