Virology Specimen Collection and Transport

Virology Laboratory, University Hospital, San Antonio, Texas


       Collect specimens for acute infections as soon after onset of symptoms as possible. Recovery of virus is best during the first 3 days after onset and is greatly reduced with many viruses beyond 5 days. Collect autopsy samples as soon after death as possible.


       Specimens be delivered promptly on ice or cold pack.


       M4 Transport Medium (M4) may be used for collection of swabs and tissue specimens as indicated below. Do not dilute body fluids by placing in M4 medium. If M4 is unavailable, 2 ml sterile saline in sterile tube may be substituted, but viral recovery may be reduced. M4 medium is suitable for virus, Chlamydia, Mycoplasma and Ureaplasma culture and detection. M4 is available in the virology laboratory, and at satellite laboratories.


       Bacterial culturette for swab transportation is not acceptable for viral culture.


       M4 tubes and other containers must be tightly sealed. Swab shafts must not protrude from inside the M4 tube. Leaking transport containers will be rejected.


       DFA Collection Kits for vesicle scrapings and HPV Collection Kits for papillomavirus detection are available in the virology laboratory.


       Specimens for infectious agent PCR detection vary widely. Please contact Virology laboratory for detailed instructions on collection, transport and storage requirements.





Collect 5-10 ml whole blood in PPT (pearl top) tube for CMV DNA PCR. Specimen should be collected and delivered to the virology laboratory prior to 12 noon. Whole blood collected for viral culture requires Medical Director consultation.

Bone Marrow

Collect 1-2 ml in EDTA (lavender top) tube.

Bronchial wash, brush or alveolar lavage


Submit 5-10 ml in sterile container; do not dilute with M4 medium.


Cervical swab

For viral culture: remove exocervical mucus with swab and discard swab. Insert fresh, sterile swab at least 1 cm into cervical canal, rotate swab for 10 s. Place swab in FTM.

For HPV detection: HPV COLLECTION KIT available in virology laboratory. Collection instructions with cervical brush are included in kit.


Collect 1-2 ml in sterile container. Submit tube with separate virology slip. For molecular assays (e.g., PCR), tube must remain unopened and be refrigerated within 4 hours of collection. Do not dilute with M4.

Eye swab

Rub sterile swab (premoistened with sterile saline) gently several times over involved surface of the eye or obtain conjunctival scrapings. Place swab in M4 tube. Do not use topical anesthetic - virus may be inactivated.


Collect 1-2 grams in sterile container. For infants, feces may be collected from diaper.

Lesion swab

Clean vesicle with sterile saline-soaked gauze. Disrupt vesicle and collect fluid with swab. With same swab, firmly swab base and margins of lesion, collecting cells. Place swab in M4 tube. Do not use disinfectant or topical anesthetic - virus may be inactivated. For lesion scraping, see Vesicle Scraping below.

Naso-pharyngeal swab

Insert swab into posterior nasopharynx, just past point of resistance. Leave in place for 1 minute or rotate to dislodge respiratory epithelial cells. Place swab in transport medium. Repeat in second naris. For small children a thin, flexible wire shaft can be used.

Naso-pharyngeal aspirate

Use suction pump connected to a catheter through a mucus trap; catheter should be French gauge 8 for infants, French gauge 12 for adults. Insert catheter into posterior nasopharynx to collect respiratory epithelial cells and secretions NOT into the anterior portion lined with squamous epithelium.


Swab lesions firmly. Place swab in M4 tube.

Pericardial fluid

Collect 2 ml in sterile container. Do note dilute with M4 medium.

Pleural fluid

Collect 2 ml in sterile container. Do note dilute with M4 medium.

Rectal swab

Swab rectal mucosa firmly. Place swab in M4 medium.


Collect saliva with 1 or 2 swabs from anterior floor of mouth and near Stenson's ducts. Place swab(s) in M4 medium.


Collect in sterile container.

Throat swab

Swab posterior pharyngeal wall, not buccal mucosa, tonsils, tongue or palate. Place swab in M4 medium. Nasopharyngeal swab is preferred, due to predominance of squamous rather than respiratory epithelial cells in throat.


Collect aseptically. Place in FTM.

Urethral swab

Express and discard any exudate. Insert flexible wire-shafted swab 2-4 cm into urethra, gently rotate swab 2-3 times and withdraw. Place swab in M4 medium. Patient should not urinate for at least 1 h prior to collection.


Collect 5-10 ml in sterile container. Patient should not urinate for at least 1 h prior to collection. Do not dilute with M4 medium.

Vesicle fluid

For Varicella culture: aspirate fluid with 26- or 27-gauge needle and syringe, or insulin or tuberculin syringe. Using one-handed technique, recap needle. Hand deliver needle and syringe to virology laboratory immediately and prior to 16:00.

Vesicle scraping

DFA Collection Kit available in virology laboratory. Clean vesicle with sterile saline-soaked gauze. Do not use disinfectant or topical anesthetic - virus may be inactivated. Disrupt vesicle with sterile scalpel blade. Scrape epithelial cells from base of lesion with scalpel; do not use swab or applicator stick. Transfer cells from scalpel blade to tube of M4 medium. Both DFA and culture can be performed on same sample.