FAQ’s for the Cervid Dual Path Platform (DPP) VetTB Assay® tests for

bovine tuberculosis (June 2020)

Q. What is the DPP test?

A. The DPP® Antibody Test is a serologic test used to test for bovine TB antibodies in 

captive cervids. 

Q. Is there a comprehensive Veterinary Services Guidance document 

describing the specific use of the DPP including detailed collection and 

submission instructions?

A. Yes, the guidance document can be found at DPP guidance Document

Q. Which cervid species can I use the DPP test on?

A. The DPP test is approved for use in elk, red deer, white tail deer, fallow deer, and 

reindeer. A pilot project is also being implemented to evaluate the test in Mule and Sika 

deer. Pilot Project - Mule/Sika

Q. What type of sample is required for the test?

A. For each cervid tested, at least 2 ml of refrigerated serum must be submitted in a 

blood serum collection tube such as a red top tube. The whole blood in the original tube 

is allowed to clot and centrifuged so the serum can be transferred to a separately 

labeled clean tube. If a serum separator tube is used it also needs to be centrifuged and 

the serum transferred to a new clean tube.

Q. Who is authorized to collect and submit samples?

A. Only Designated Accredited Veterinarians who have received supplemental training 

on TB testing and the DPP testing are authorized to collect and submit samples.

Q. I am an accredited veterinarian, but have not been trained as a Designated 

Accredited Veterinarian. May I submit samples using the DPP test?

A. No. You must be a Designated Accredited Veterinarian who has received 

supplemental DPP test training in order to collect and submit samples using the DPP 

test on cervids.

Q. How can I become a Designated Accredited Veterinarian?

A. Contact your local APHIS Veterinary Services Area office to receive information on 

the supplemental DPP test training and to become a Designated Accredited 

Veterinarian. A list of area offices can be found at: AVIC List
Q. If I am a Designated Accredited Veterinarian, may I choose either the SCT skin 

test or the DPP test to assess the status of TB in cervids?

A. Yes, either the DPP or the SCT may be selected by the veterinarian. Animals that 

are non-negative on the DPP will be retested after 30 days with the DPP. Animals 

that are responders on the SCT will be retested with the Comparative Cervical Test

(CCT).

Q. Why is additional training needed if the test only involves submitting a blood 

sample?

A. In order to perform bTB testing of any kind (skin testing, serological testing, etc.) in 

cervids, a veterinarian must be knowledgeable not only in technique, but also in the 

regulations under the National bTB Eradication Program. Additionally, many tests that 

are performed must adhere to additional requirements such as for import/export and 

establishing and maintaining accredited cervid herds. The additional training provides 

this information.

Q. Can I send the serum sample to any laboratory for testing?

A. No. Serum samples must be sent to the National Veterinary Services Laboratory 

(NVSL) in Ames, Iowa. Be sure to obtain permission from the APHIS VS Area 

Veterinarian in Charge (AVIC) in your State to submit the sample(s) to NVSL prior to 

sample shipment. The AVIC list is AVIC List

Q. When do samples need to be received by NVSL?

A. Samples must be received by NVSL within 5 days of collection. Samples must be 

received Monday through Friday and must not be shipped to arrive at NVSL on 

weekends or holidays. Samples received on the weekend will be considered to have 

been received on the following Monday. Samples received on a federal holiday will be 

considered received the following day and classified invalid if this exceeds 5 days from 

collection.

Q. Will the test be conducted on samples received more than 5 days after 

collection?

A. Samples received after 5 days will be processed at NVSL and user fees will be 

collected for this service. However, the test results will be classified as invalid.

Q. Do all States and Countries accept the DPP as an official bTB test for cervid 

herd accreditation and import purposes?

A. You must verify with the State of residence of the animals, the importing State, or 

the importing country to determine if their animal health regulations allow the use of 

the DPP as an official testing method for cervids.
Q. If I am also testing a cervid for brucellosis, may I collect one blood sample and 

have it tested for both bTB and brucellosis?

A. No. When also testing a cervid for brucellosis, an additional tube of whole, clotted 

blood must be collected and submitted to an approved brucellosis testing laboratory 

accompanied by the official brucellosis testing chart VS Form 4-33,.

Q. What happens if the DPP test result is positive?

A. If the DPP test has a positive result, the animal will be subject to quarantine and a 

second DPP test will be perform no sooner than 30 days later. Animals testing positive 

on the second test will be classified as reactors.

Q. Can cervids that respond to the SCT skin test then be re-tested with the DPP?

A. No. The TB skin test and serologic tests cannot be used in combination or 

interchangeably. Cervids classified as responders by testing positive on the single 

cervical skin test (SCT) must be retested by regulatory veterinarians using the 

comparative cervical skin test (CCT). 

Q. Can accredited veterinarians or producers obtain the DPP test for their own 

use as an “unofficial test”?

A. No. Any tuberculosis test conducted in species under the National TB Eradication 

Program is an official test as defined in the Title 9 Code of Federal Regulations, Part

77. All results must be reported to State animal health officials within a specified time 

after the test was administered.

Q. Is specificity affected by exposure to other mycobacterial antigens known to 

cross-react in bovine TB tests, such as Mycobacterium avium or in herds infected 

with Johne’s (Mycobacterium paratuberculosis)?

A. The antibodies detected by the DPP do not cross-react to antibodies for 

Mycobacterium avium, M. paratuberculosis, or most environmental mycobacteria. 

However, M. kansasii has certain common antigens with M. bovis, therefore, animals 

exposed to M. kansasii may have a DPP false positive test result. The final culture 

results on the animal tissues will determine which Mycobacteria is present. An animal is 

classified negative to bTB when Mycobacteria other than M. bovis are cultured.

Q. May I perform the DPP test on animals that have only producer tags as 

identification?

A. No. Official identification recognized by APHIS must be present on each animal 

tested with the DPP. Identification numbers must be recorded on the VS 10-4/10-4a and 

VS 6-22 to correspond to the sample submitted for testing.

Q. How can I receive a DPP test kit?
A. Designated Accredited Veterinarians may submit blood samples using their own 

compliant shipping container using 24-hour delivery service. The US Postal Service 

does not deliver directly to NVSL. You may also order a DPP test kit that consists of 

written instructions, a VS 10-4/10-4a Laboratory Submission Form, an ice pack, and a 

paid shipping label to NVSL. For more information on how to order a DPP test kit or on 

compliant shipping boxes, please contact NVSL at (515) 337-6200 or email at

NVSL_userfee@aphis.usda.gov

.

Q. What is the NVSL laboratory charge to conduct the DPP test? 

A. NVSL fees can be accessed through our catalog at NVSL Catalog or contact NVSL 

by email at NVSL_userfee@aphis.usda.gov

Q. How are payments made to NVSL for the DPP test.?

A. The Designated Accredited Veterinarian submitting the sample will be responsible for 

test payment. NVSL accepts the following payment methods

 Check, money order, or bank draft (US dollars) -- make payable to USDA

 Credit card (Visa, MasterCard, American Express, or Discover) -- include the credit 

card number and expiration date on the submission form

 Bill to USDA Account -- write the account number in the designated area on the 

submission form

Contact NVSL at (515) 337-6200 for more information. User Fee Payment

Q. When will I receive the test results?

A. Results will be reported to the submitting Veterinarian within 5 business days after 

samples are received by NVSL.

Q. How will the test results be reported?

A. Test results will be provided to the submitting Veterinarian by email, FAX, or mail. 

Veterinarians may specify preferred methods for receiving results on the submission 

form or when they set up their account with NVSL.