Heartworms live approximately 1 to 2 years in cats and ectopic infections are not uncommon. Clinical signs of feline heartworm disease include, among others, vomiting, coughing, respiratory distress, central nervous system abnormalities and acute death.

 

Indications

HESKA Solo Step FH is a diagnostic tool developed specifically to assist veterinarians in detecting D. immitis infections in cats. This test will also aid in determining prevalence rates of D. immitis infection in the cat population.

Directions for Use

The test cassette is for use in detecting IgG antibodies against D. immitis in serum, plasma or anticoagulated whole blood from cats.

Required Materials

1. A sample of feline serum, plasma or anticoagulated whole blood
2. Test cassette (provided)
3. Pipette (provided)
4. Timer or clock

 

Procedure

1. Open the foil package and place the test cassette on a flat solid surface (Figure 1).
2. Using the pipette, draw up the patient sample into the stem portion of the pipette. Do not fill the bulb (Figure 2).
3. Holding the pipette vertically, dispense 3 drops of the sample into the round sample well of the test cassette (Figure 3).
4. Allow the test cassette to sit undisturbed for 5-10 minutes (Figure 4).
5. Read the results in the rectangular Results Window 5 minutes after applying plasma or serum. For anticoagulated whole blood, read results 10 minutes after application. A blue line (Procedural Control Line) must appear on all samples, and a red line (Test Line) may or may not appear (Figure 5).

 

Interpretation of Test Results

Procedural Control Line (C): You must see a blue line within 5 minutes of adding serum or plasma, or within 10 minutes of adding anticoagulated whole blood, for the test to be valid. This blue procedural control line indicates proper flow of the sample through the test cassette. If the blue line does not develop, the test is invalid and should be repeated. Discard the test cassette, and repeat the test with a new test cassette.

Test Line (T): Any visible red line within 5 minutes of adding serum or plasma, or within 10 minutes of adding anticoagulated whole blood, indicates a positive result. Antibodies to D. immitis are present. This means one or more of the following:

• Adult heartworms are present in the heart and/or pulmonary arteries.
• The cat is infected with late L4 or adult worm(s).
• Heartworm infection has been cleared, but antibodies are still present.
• Ectopic heartworm infection may be present.

In the presence of suggestive clinical signs and other supportive diagnostic data (e.g., radiographic findings, echocardiographic findings, etc.), a positive result will help confirm cardiovascular heartworm disease.

No red line within 5 minutes of adding serum or plasma, or within 10 minutes of adding anticoagulated whole blood, indicates a negative test result. There are no antibodies to D. immitis present. This means one of the following:

• The cat is not infected with D. immitis.
• The cat was infected less than 60 days prior to collection of the sample.

If a negative result is obtained and clinical signs are present, a retest within 2-3 months is recommended. Additional diagnostic tests should be employed to rule out other causes of the clinical signs.

 

Sample Collection and Storage

Anticoagulated Whole Blood: Collect an anticoagulated blood sample in EDTA, heparin or citrate using standard clinical laboratory procedures. Anticoagulated whole blood samples should be tested within 24 hours of drawing. If delays are expected between sample collection and testing, anticoagulated whole blood samples should be stored either on ice or refrigerated (2 - 7° C) but should not be frozen. If anticoagulated whole blood samples cannot be tested within this period of time, separate plasma by centrifugation and store as described below.

Plasma: Collect an anticoagulated blood sample using standard clinical laboratory procedures. Separate plasma by centrifugation. Plasma samples may be stored refrigerated (2 - 7° C) for up to 72 hours; for longer storage, freeze at or below -20° C in vials with air-tight seals.

Serum: Collect and prepare serum samples using standard clinical laboratory procedures. Serum samples may be stored refrigerated (2 - 7° C) for up to 72 hours; for longer storage, freeze at or below -20° C in vials with air-tight seals.

Precautions

1. Do not expose the test cassette to direct sunlight.
2. Do not use to test species other than cats.
3. After 10 minutes, a very faint red line may appear in the Results Window with samples from some cats which are negative for heartworm infection.
4. Do not use the test cassette more than once.
5. Use the test cassette immediately after opening the foil pouch.

Storage and Stability

1. Store at room temperature (15 - 30° C [59 - 86° F]).
2. See package for expiration date.