DNA Testing


Sample Collection & Shipping Instructions for DNA Tests

Please follow these instructions for DNA testing. You need to send either a blood sample or cheek brushes (2 per animal), but not both. We prefer a blood sample. You may purchase the cheek brushes from the following websites www.ezswabs.com or www.dnakit.eu . If you have further questions, please email PennGen@lists.upenn.edu.

A Note About Handwritten Forms: We no longer accept handwritten submission forms, so please make sure that you create an account for yourself on the PennGen Sample Submission Application, log in to your account, fill in the animal information, select the appropriate test to obtain a Submission ID for each animal, and then print the submission sheet and mail it along with the sample.

Blood Sample Collection (performed by a veterinary clinician or nurse)

  1. Label an EDTA tube with animal’s call name and owner’s last name, date.

  2. Draw 1–2 ml of animal's blood into the labelled tube.

  3. Blood sample must be kept cold (but not frozen) until shipping.

  4. Blood tubes need to be wrapped in bubble wrap or other protective packaging and then sealed in a Ziploc bag.

  5. Complete the online submission for each animal, print the submission sheet, and mail it along with the sample to the address printed on the submission sheet.

  6. These samples do not need to be shipped on ice packs and you may ship on any day of the week.

  7. All samples for DNA testing can be shipped by regular mail, but we recommend having a tracking number for your shipment, so that you can track the delivery of your samples. If you are using USPS or other government run shipping service expect a delay in delivery (their expected delivery dates are not predictable because the USPS delivers directly to to the University first, for subsequent distribution to our PennGen labs). If you prefer a prompt delivery, we recommend using a private shipping service (such as FedEx, UPS, DHL) which deliver directly to our laboratories or building.

  8. For international shipments, a customs declaration and proforma invoice must be completed and included with the shipment (outside and inside package; see international shipping).

Cheek Brush Sample Collection

Cheek brushes (also called Cytology brushes) can be purchased from www.ezswabs.com or www.dnakit.eu.

  1. Please note, the kind of brushes you use must be:
    • Sterile
    • Wrapped individually or two per pack
    • The wrapper must be intact/unopened before sample collection
    • The brush handles (plastic only; we no longer accept swabs with wooden handles) must be longer than 5 inches and the thickness of those handles must be less than 0.3 centimeters in diameter
    • We prefer brushes over swabs, because they fail less often
    • Do NOT use culture swabs (these are swabs that come with plastic tube containers with culture media in them)

  2. Isolate the animal from other animals, toys, and other sources of oral contamination for several hours before sampling.

  3. To avoid contamination with food, do not feed or water the animal within 3 hours of collecting the sample.

  4. Check the animal's mouth for food or other substances. If there is something, clean/rinse the animal's mouth and wait for another hour.

  5. The person collecting the sample should avoid touching inside the animal's mouth.

  6. Wash your hands before you collect the sample or wear disposable gloves.

  7. Label the packages/sleeves that contain the cheek brushes with the animal’s call name and the owner’s last name.

  8. Open the end of the brush package that shows the word “peel” printed on it. Be careful not to touch the brush end as you remove it; it should not touch anything except inside the animal's mouth or inside the package it came in.

  9. You may also wish to ask a second person to gently restrain the animal’s head while you collect the sample.

  10. Insert brush end between the animal’s gums and inside of the cheek. Roll the brush on the inside surface of the cheek for 15–20 seconds. Make sure that the brush is in contact with the cheek and not just with the saliva. To enhance sample collection, gently push on the outside of the cheek while rolling the brush, this will press the brush between the cheek and gum.

  11. Hold the brush in your hand for at least a minute while it air dries. Do NOT blow on the brush.

  12. Return brush to its original package, allow it to dry completely, and then tape the opened end shut.

  13. Repeat steps 7–12 for the second brush using opposite side of the mouth. Two brushes are needed for each animal tested.

  14. Secure brushes from each animal in a separate paper envelope.

  15. If you plan to test another animal, remember to wash your hands before you start with the next animal or change gloves.

  16. To reduce the chance of microbial growth on the brushes after sample collection do not freeze them or store them in a refrigerator where condensation can occur.

  17. Complete the online submission for each animal, print the submission sheet, and mail it along with the sample in a sturdy mailing envelope to the address printed on the submission sheet. Write "Do Not Bend" on the mailing envelope.

  18. All samples for DNA testing can be shipped by regular mail, but we recommend having a tracking number for your shipment, so that you can track the delivery of your samples. Do NOT ship them on ice. If you are using USPS or other government run shipping service expect a delay in delivery (their expected delivery dates are not predictable because the USPS delivers directly to to the University first, for subsequent distribution to our PennGen labs). If you prefer a prompt delivery, we recommend using a private shipping service (such as FedEx, UPS, DHL) which deliver directly to our laboratories or building.

  19. For international shipments, a customs declaration and proforma invoice must be completed and included with the shipment (outside and inside package; see international shipping).

Concerns Associated with Cheek Brush Sample Submissions


We have been accepting cheek brush samples for our DNA tests because it simplifies the process of sample submission and reduces the associated expenses for the submitter. However, it is important that you understand the following concerns/risks with submitting a cheek brush sample:

  1. Misidentification/Mislabeling: Especially when collecting samples from siblings/littermates, it is possible to misidentify the animals or to mislabel the collected samples. This will obviously lead to inaccurate results.

  2. Contamination: DNA tests are contamination-sensitive; even miniscule amounts of contamination from another animal or human could lead to false results. Therefore, it is important to be attentive during sample collection and to follow the instructions.

  3. Unweaned Puppies/Kittens: Do NOT collect cheek brush samples from unweaned puppies/kittens due to the risk of maternal contamination. For testing unweaned puppies/kittens, have a veterinarian collect 0.5 to 2 ml of EDTA blood, but not more than 0.5 ml per 100 grams of body weight.

  4. No or Insufficient DNA: If too few cells are removed from the cheeks, it will result in insufficient DNA yields and the test will fail. While there are other factors that could cause insufficient DNA yields, it is most likely due the sample submitter’s failure to follow the instructions appropriately. We ask for at least two brush samples to be submitted from each animal, if both of them fail the test, it means that something went wrong before we received the samples (either the samples were not collected/shipped properly or some other shipping issue like customs irradiation of the package). There have been instances where the submitter sent unopened/sterile brushes by mistake, which obviously resulted in no DNA yield as well as instances when the sample grew mold and did not yield results.

  5. Resubmission: When a test fails due to No/Insufficient DNA yield, we ask for a resubmission but both the failed submission and resubmission may be charged. When we receive a sample that fails, due to low DNA or contaminated DNA due to mold growth, we must perform multiple tests before we conclude it has no/insufficient DNA. 

  6. Our test reports specify the type of sample submitted.