Rabies DFA

Rabies DFA

  • Laboratory Location – Shreveport Laboratory
  • CPT Code – 88346
  • Synonyms – FA Test
  • Test Description - An impression smear is made from potientially rabies-infected tissue and acetone fixed. Fluorescein labeled monoclonal anti-rabies antibodies are incubated on the smear. If antigen-antibody binding occurs in infected tissue, it can be observed using a fluoresence microscope.

Possible Results

  • Negative
  • Positive
  • Unsatisfactory

Reference Range

  • Presence or absence

Specimen Requirements

  • Specimen Type - Heads of animals which have bitten, scratched, or otherwise exposed a human being except rodents and lagomorphs unless the rodents or lagomorphs attacked in an unprovoked manner and exhibit neurological signs. Exceptions to the specimens accepted may be made by the State Public Health Veterinarian at (504) 219-4593, State Epidemiologist (504) 568-8313 or the Infectious Disease Epidemiology Section 24 hour# 1-800-256-2748.
  • Specimen Container(s) - Place in a clean, leak proof plastic bag and seal.
  • Minumum accepted volume -The entire brain must be submitted. Identifiable sections of brain stem and cerebellum or hippocampus must be examined so care must be taken to not destroy the brain when the animal is killed.

Specimen Collection Instructions

After decapitiation, the head should be placed in a clean, leak proof plastic bag and cooled immediately to 4°C. There is no need to decapitate very small animals such as bats. Latex or rubber gloves should be worn and care should be taken to avoid getting the animal's body fluids into open cuts or sores.

Complete Rabies Lab Request and Report Form (Lab 32)

Storage and Transport Instructions

Specimens (in plastic bags) may be placed on wet ice or ice packs in an ice chest or other watertight containers to be delivered to the laboratory. The ratio of ice to specimen should be greater than 2:1. The specimen should be completely surrounded by ice. Specimens shipped on the state sample truck must have tape labeled "RABIES SPECIMEN" on all sides of the outer container and be accompanied by an OPH Rabies Specimen Log Sheet stating the location/date/time that the specimen is picked up and delivered. The shipper is obligated to follow all laws and regulations for labeling diagnostic specimens. Specimen transit time to the laboratory should be as short as possible by the quickest and most direct means available.

Causes for Rejection

  • Extensive damage by trauma/ gunshot or advanced decomposition

Limitations for the Procedure

The test result is not absolute. Treatment of the patient will have to be made based on test results, epidemiological data and cercumstances surrounding the exposure. 

Interfering Substances



  • Rabies Virus Antigen Detection for Diagnosis of Rabies in Animals - Direct Fluorescent Antibody Procedure, Revised 2002, Louisiana Office of Public Health, Div. of Laboratories, Gita Talati and Stephen J. Martin Ph.D.
  • FITC Anti-Rabies Monoclonal Globulin (package insert), Fujirebio Diagnositcs, 5/04, 201 Greeat Valley Parkway, Malvern, PA
  • Rabies Specimen Packaging and Transport, Sanitarian Services Memorandum No.03/2002, James P. Antoon, August 6, 2002.
  • Laboratory Examination of Animal Heads for Rabies, P502, Sharon Howard, Assistant Secretary LDH-OPH, June 19, 200


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