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ViraCHEK/FeLV Kilo Pack

This page contains information on ViraCHEK/FeLV Kilo Pack for veterinary use.
The information provided typically includes the following:
  • ViraCHEK/FeLV Kilo Pack Indications
  • Warnings and cautions for ViraCHEK/FeLV Kilo Pack
  • Direction and dosage information for ViraCHEK/FeLV Kilo Pack

ViraCHEK/FeLV Kilo Pack

This treatment applies to the following species:
Manufacturer: Zoetis

Feline Leukemia Virus Antigen Test Kit

For the Detection of Feline Leukemia Virus


Feline Leukemia Virus (FeLV) is a highly contagious oncogenic RNA virus that causes both neoplastic and non-neoplastic disease in cats. Diseases caused by FeLV include lymphosarcoma, myelogenous leukemia, thymic atrophy, nonregenerative anemia and panleukopenia-like disease. Because FeLV is immunosuppressive, it predisposes infected cats to a variety of secondary diseases.

Rapid identification of infected cats allows them to be separated from non-infected cats to prevent the spread of FeLV. ViraCHEK®/FeLV uses highly specific antibodies to quickly identify FeLV-infected cats. The group specific antigen, p27, is found in high levels in infected cats and its presence is diagnostically definitive for FeLV infections. ViraCHEK®/FeLV is an immunoenzymatic assay using antibodies that specifically recognize p27 in cat blood.

Since infection may be transient in cats that develop immunity, antigen-positive animals should be retested in 8 to 12 weeks. A positive second test indicates persistent infection. A negative test indicates clearance of the virus.

Test Principles

The plastic wells contain antibodies directed against the FeLV group specific antigen, p27. A monoclonal antibody directed against p27 is labeled with horseradish peroxidase (HRP). The specimen (whole blood, plasma or serum) is incubated simultaneously with the solid phase and enzyme-labeled antibodies. If present, p27 group specific antigen is bound to the well and enzyme-linked antibody at the same time. The free enzyme-linked antibody is washed away and a chromogenic substrate is added. The development of a distinctly blue color indicates the presence of FeLV. In the absence of FeLV, no color change will be observed.

ViraCHEK®/FeLV is highly specific, sensitive and simple to perform. Test results for circulating antigen can be obtained in 10 minutes or less. Following exposure a cat may test positive within 14 days. Persistent infections will remain positive while transient infections may revert to negative within 8 to 12 weeks. Retesting after that time is recommended.


Anti-FeLV Coated Wells


Positive Control (Red Cap)

3.5 ml

Reagent 1 - HRP Antibody Conjugate (Blue Cap)

60 ml

Reagent 2 -Chromogenic Substrate Buffer (Purple Cap)

2 x 60 ml

Well Holders


Negative Control (Gray Cap)

3.5 ml

Materials required but not provided:

Precision pipet and tips

Distilled or deionized water or saline

Materials suggested but not provided:

Multi-channel pipet

Reagent basins

Sample Information

50µl (0.05 ml) of feline whole blood, plasma or serum is required. Whole blood and plasma must contain an anticoagulant. Serum and plasma samples may be stored at 2° to 7°C (36° to 45°F) for 7 days; 24 hours for whole blood. For longer periods, serum and plasma (not whole blood) may be stored at -20°C. Hemolyzed or lipemic samples can be used, however, severely hemolyzed or lipemic samples may produce background color. When in doubt, obtain a better quality sample.


1. Prior to use, allow kit to come to room temperature (21° to 25°C; 70° to 78°F).

2. To prevent contamination, do not return reagent to bottle.

3. Do not mix reagents between different serials.

4. Do not expose kit to direct sunlight.

5. Do not use expired components.

6. Follow instructions carefully.


Storage And Stability

Store the test kit at 2° to 7°C (36° to 45°F). Do not freeze. Reagents are stable until expiration date provided they have been stored properly.

ViraCHEK®/FeLV Test Procedure

NOTE: Use Anticoagulated WHOLE BLOOD, PLASMA or SERUM Samples.

Prior to use, allow kit components to come to room temperature (21° to 25° C; 70° to 78° F).

Test Procedure

Step 1: Determine required number of antibody coated wells. One well for the Positive Control, 1 well for the Negative Control and 1 well for each sample. Remove required number of plates and/or removable wells. Place removable wells in the well holder, leaving wells attached to each other.

Step 2: Place 1 drop or 0.05 ml of Positive Control into the first well. Place 1 drop or 0.05 ml of Negative Control into the second well. Place 0.05 ml of sample into the next well. Using a separate pipet tip for each sample, place 0.05 ml of each additional sample into subsequent wells.

Step 3: Add 0.05 ml of Reagent 1 (Conjugate) into each well. Tap well holder (without splashing) for 15 seconds to mix.


Step 4: Discard fluid in wells into sink or appropriate container. Invert and blot firmly against a paper towel.


Distilled/deionized water or normal saline can be used with serum and plasma.

Wash wells vigorously by directing a forceful stream of distilled/deionized water or normal saline into each well. (Oversplashing will not contaminate adjacent wells.) Shake out residual liquid. Repeat wash at least 5 separate times. Wells cannot be overwashed. Invert and blot against a paper towel to remove final drops of water. IF SALINE IS USED TO WASH WELLS, USE DISTILLED/DEIONIZED WATER FOR FINAL WASH.

Step 6: Add 0.10 ml of Reagent 2 (Chromogenic Substrate Buffer) to each well. Tap well holder (without splashing) for 15 seconds to mix.

WAIT 5 MINUTES. Read results.

Interpretation Of Results

Controls: For the test to be valid, the Positive Control should be distinctly blue and the Negative Control should be clear.

Samples: Positive samples will be blue. Color intensity will vary with level of FeLV antigen present.

Negative samples will be clear.


SYNBIOTICS CORPORATION, 16420 Via Esprillo, San Diego, CA 92127

U.S. Veterinary License Number 312


NAC No.: 11150571

Telephone:   269-359-4414
Customer Service:   888-963-8471
Every effort has been made to ensure the accuracy of the ViraCHEK/FeLV Kilo Pack information published above. However, it remains the responsibility of the readers to familiarize themselves with the product information contained on the US product label or package insert.

Copyright © 2018 North American Compendiums. Updated: 2018-04-26