Rabies direct fluorescent antibody test

TEST DESCRIPTION

Fluorescent antibody test to detect rabies virus in the brain tissue of suspected rabid animals. Brain tissue is exposed to fluorescent anti-rabies antibodies. In the presence of rabies virus, antigen-antibody complexes will form. These antigen-antibody complexes are visualized by fluorescence microscopy. Positive reactions demonstrate bright apple-green fluorescence of particles ranging in size and morphology from “dust particles” to prominent cytoplasmic inclusions.

Methodology

Direct fluorescent antibody

Reference range

Negative

TEST FREQUENCY & RESULT AVAILABILITY

Performed daily for priority cases; weekly for low suspect cases. Results are typically available within one business day for priority cases.

ACCEPTABLE SPECIMEN TYPES AND COLLECTION

• Bats
• Mouse-sized mammals
• Animal heads of larger mammals
• Detailed collection instructions appear below

SPECIMEN STORAGE & TRANSPORT

Specimens should be kept refrigerated during storage and transport. When stored in a cooler, multiple ice packs should be used to maintain refrigerated temperatures. DO NOT FREEZE unless there are expected delays in delivery to the laboratory. Frozen specimens cannot be tested until they thaw, which will lengthen the test turnaround time.

Note: It is important to follow the guidelines below for safely securing packaging that contains animals for rabies testing. Individuals handling animals should be aware of the risks and consequences of rabies exposure.

REJECTION CRITERIA

• Living animals
• A qualitative assessment of the condition of each sample will be made upon arrival to the laboratory, and the specimen may be deemed unsatisfactory for testing for the following reasons:
  1. Substantial green color
  2. Liquefied brain tissue
  3. Desiccated brain material
  4. Unrecognizable gross anatomy
  5. A substantial loss of tissue during staining indicative of sample deterioration
  6. Presence of bacteria on the stained slide indicative of sample deterioration
  7. No brain stem available

Note: The laboratory test what appears to be unsatisfactory material when deemed to be appropriate. When these specimens are tested, a negative finding for rabies cannot be made/ In the absence of positive fluorescence, the specimen will be resulted as unsatisfactory rather than negative.

 CODES

CPT: Not applicable
LOINC: 6532-6
Test code: 6000

TEST FEE

Refer to the current fee schedule.

DETAILED SPECIMEN COLLECTION INSTRUCTIONS

For Animal Heads

1. Only veterinarians, animal control officers, or individuals who have been appropriately trained and vaccinated should remove an animal’s head for rabies testing. This procedure should be performed in a well-ventilated area using personal protective equipment (PPE).
2. Ensure the animal head has stopped bleeding before placing into a plastic bag. Then place the first plastic bag into a second plastic bag and seal it with a rubber band or tape to prevent leakage. 
   1. If submitting multiple specimens, use separate bags and label the outside of each bag with an identification number that matches the information on the requisition form.
3. Place the double-bagged specimen into an insulated container. Include enough ice packs in the container to keep the specimen cold during transport.
4. Complete the Rabies Testing Form (i.e., requisition).
   1. Ensure the contact’s name and number are provided on the form.
   2. Incomplete requisition forms will delay test results. 
5. Place the requisition in a Ziplock bag to prevent contamination and tape to the corresponding specimen bag.  Do not use staples.  

 For Bats or Mouse-sized Mammals

1. Submit the entire animal if it is a bat or a mouse-sized mammal.
2. Submit the animal in a double plastic or Ziplock bag. 
3. Place the double-bagged specimen into an insulated container with ice packs to keep the sample cold during transport.
   1. If submitting multiple specimens, use separate bags and label the outside of each bag with an identification number that matches the information on the requisition form.
4. Complete the Rabies Testing Form. 
   1. Ensure contact’s name and number are provided on the form.
   2. Incomplete requisition forms will delay test results. 
5. Place the requisition in a Ziplock bag to prevent contamination and tape to the corresponding specimen bag.  Do not use staples.