Test Results - University of Georgia College of Veterinary MedicineUniversity of Georgia College of Veterinary Medicine

A guide to help you interpret your report

Once you submit a sample for testing to the IDL, you will then receive a report back that will discuss what was found. Below is a list of what types of interpretations you can expect for each test we offer.

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

A

Adenovirus in situ hybridization

Results Report states whether sample is Positive or Negative.

Aleutian Disease Virus Panel

Results report states sample is either Positive or Negative and gives titer results.

Antinuclear Antibody Titer

There is no consensus as to what is a significant ANA titer in animals. Many investigators feel that titers > 10 are significant while others feel that titers > 40 are significant. A negative result does not rule out systemic lupus erythematous or other immune-mediated diseases as these conditions can occur without detectable antinuclear antibodies.

Atoxoplasma PCR

Results report states sample is either Positive or Negative

**Since Atoxoplasma has a predilection for mononuclear cells, the best tissues for PCR testing of birds for Atoxoplasma are liver and spleen at necropsy and the preferred sample from live birds is whole blood. Testing of feces does not distinguish between extraintestinal and intestinal Isospora spp. Therefore, a positive fecal sample is not predictive of Atoxoplasma spp.

Avian Bornavirus

Results report states sample is either Positive or Negative

Avian Polyomavirus ISH (psittacine only)

Results report states sample is either Positive or Negative

Avian Polyomavirus Results

As in the case for most viruses, the most effective way to control the continued spread of polyomavirus is through vaccination.

DNA Probe Testing:

DNA probe test is Positive: indicates that the target segment of polyomaviral nucleic acid has been detected in the submitted sample.
DNA probe test is Negative: indicates that the target segment of polyomaviral nucleic acid has not been detected in the submitted sample.
As a rule, psittacine birds infected with avian polyomavirus will either die or will seroconvert and recover. In non-budgerigar psittacine birds, shedding of polyomavirus may occur from weeks (typical) to months while the bird’s immune system is clearing an infection. Repeat testing in > 90 days can be used to determine if viral nucleic acid is still detectable in samples collected from a bird. The detection of polyomaviral nucleic acid in any sample collected from a bird indicates a contaminated environment e.g. aviary, pet shop, home, plane, car to which the bird has recently been exposed. This warrants a search for the source of the virus.Isolation of a Positive bird, vaccination of other birds exposed to the same contaminated environment, thorough and repeated cleaning/disinfecting and environmental testing are recommended to reduce the unabated spread of the virus.

Antibody Testing

As a rule, psittacine birds infected with avian polyomavirus will either die or will seroconvert and recover. An assay to detect virus-neutralizing antibodies can be used to determine if a bird has been infected with polyomavirus or has been successfully vaccinated. Demonstration of a rising titer in paired serum samples indicates a recent infection while a decreasing titer in paired serum samples indicates that the humoral immune system is no longer being stimulated. An antibody titer <20 is considered negative, a titer >= 20 is considered positive. A titer as low as 20 has been shown to indicate a sufficient immune response to protect a vaccinate from experimental challenge, although current research with protein specific vaccines suggests that detectable virus-neutralizing antibodies may be unnecessary to protect a vaccinate from challenge. An antibody titer >= 80 is considered high. While the rate with which virus-neutralizing antibody levels decrease will vary with the individual, the detection of rising or high antibody titers suggests that a bird has recently been exposed to the virus (aviary, pet shop, bird show, home, plane, car, etc.). This warrants a search for the source of the virus. Isolation of an actively infected bird, vaccination of other birds exposed to the same contaminated environment, thorough cleaning, disinfecting, and environmental testing are recommended to reduce the unabated spread of the virus.

Avian Histopathology

Results report gives explanation.

Avian Necropsy

Results report gives explanation.

Avian Gastric Yeast

Results Report states whether sample is Positive or Negative.

Results report states sample is Positive or Negative for each test.

B

Bartonella henselae PCR

Results report states sample is Positive or Negative.

Bornavirus

Results report states sample is Positive or Negative.

C

Canine Distemper Virus RT-PCR

Results report states sample is Positive or Negative.

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Canine Heartworm (Dirofilaria immitis) Antigen

The heartworm antigen test is run with Synbiotics DiroCHEK Antigen Test Kit. This test detects antigen shed by adult female heartworms, Dirofilaria immitis. Research indicates that this antigen is in the circulation when adult heartworms are present in the animal or have been present within the last 60 days. A negative reaction in the antigen test does not eliminate the possibility of a heartworm infection. In animals with an early infection or in animals with small numbers of heartworms (10 or less), the level of circulating antigen may be below the detection threshold of the ELISA test. The animal may have an all male heartworm infection.

Chlamydia sp. immunohistochemistry

Results report states sample is Positive or Negative.

Chlamydia Results

Until a safe subunit vaccine is available, testing of birds for the presence of chlamydial infection followed by the isolation and treatment of infected birds is the only method to reduce the spread of this organism among Psittaciformes.

DNA Probe Testing:

DNA probe test is Positive: indicates that the target segment of chlamydial nucleic acid has been detected in the submitted sample.
DNA probe test is Negative: indicates that the target segment of chlamydial nucleic acid has not been detected in the submitted sample.

Epizootiologic and seroprevalence studies suggest that psittacine birds infected with Chlamydia spp. will either die, develop a chronic active infection, or will seroconvert and recover. Birds which are clinically ill or with chronic active infections are a risk for transmitting the organism. The detection of chlamydial nucleic acid in any sample collected from a bird indicates that the organism was contaminating the environment to which the bird has recently been exposed (aviary, pet shop, bird show, home, plane, car, etc.) and warrants a search for the source of the organism. Isolation of the infected bird, antimicrobial therapy, testing of other birds exposed to the same contaminated environment, thorough cleaning, disinfecting, and environmental testing may be recommended by your local health officials to reduce the unabated spread of the organism.

Antibody Testing

IFA

A titer of 1:25 or greater is considered a positive titer.

To determine the clinical significance of this value a second titer needs to be determined in 2 to 3 weeks. When comparing titers, a rising titer of at least 2 dilutions is consistent with acute infection.
A falling titer of at least 2 dilutions is consistent with recovery phase. A constant titer suggests that the bird has been previously infected and mounted a detectable immune response. A titer of 1:5 must be repeated in 2 to 3 weeks to determine any clinical significance.

EBA (elementary body agglutination)

A titer of 1:10 or greater is considered a positive titer.

Agglutination assays inherently favor the detection of IgM, which the body develops during the early phase of an infection. To determine the clinical significance of a titer, a second titer needs to be determined in 2 to 3 weeks. When comparing titers, a rising titer of at least 2 dilutions is consistent with acute infection. A falling titer of at least 2 dilutions could indicate transition from an early phase IgM antibody response to a later phase IgG antibody response or that the bird has mounted an effective immunologic defense and is clearing the infection. PCR-based testing of a conjunctival, choanal and cloacal swab in combination with IFA serologic assays are recommended to help determine the state of infections. A constant titer suggests that the bird has been previously infected and mounted a detectable immune response.

Circovirus in situ hybridization

Results Report states whether sample is Positive or Negative.

Cryptococcal Antigen Titer

A titer of 0 rules out presence of disseminated infection, but not the possibility of a localized lesion.

Titers > 0 and < 8 suggest prior infection; however, there is a high rate of false positive titers that are < 8. If this is the first titer a second follow-up titer is recommended along with other lab tests such as a microscopy and culture. In cases where animals have completed therapy and are being monitored, titers < 8 in conjunction with resolution of clinical signs usually indicates completion of drug therapy. Titers should be rechecked periodically (every 2-6 months) for 1-2 years following completion of drug therapy.

Titers =/ > 8 are considered positive. If the test is used for monitoring drug therapy, it may be 2-4 months before a significant decrease in titer occurs. Treatment may be considered successful if follow-up titers for one year are
< /= 20. If therapy is completed and titers are still > 20, treatment should be continued. If further treatment is not possible, then check titers every 2 months.

Culture and Sensitivity

See results report.

Canine Circovirus

Results Report states whether sample is Positive or Negative.

D

DNA in situ hybridization tests

Results report states whether the sample is Positive or Negative.

E

Ehrlichia canis Antibody Titer

Titers < 64 are negative.

Titer = 64 indicates a borderline positive result, a recheck in 2 weeks is strongly recommended.
Titer =/> 128 are positive for antibody to Ehrlichia and are indicative of prior infection with Ehrlichia canis or a closely related species.

Exotic animal necropsy

See results report.

Exotic animal histopathology

See results report.

F

Feline Disease Panel (Toxo, FIP, FIV, FeLV titers)

See individual tests(Toxo, FIP, FIV, FeLV titers) for interpretation.

Feline Leukemia Virus Antigen

The Feline Leukemia Virus (FeLV) antigen test is run using the Synbiotics ViraCHECK antigen test kit. A positive antigen test indicates that the cat has circulating FeLV antigen. Following exposure, a cat may test positive within 14 days. Approximately 70% of cats testing positive for FeLV will be able to clear the infection and become immune to the virus. Cats with persistent infections will remain positive while transient infections may revert to FeLV antigen negative within 8-12 weeks. It is recommended that cats that test positive for FeLV be isolated and retested after 2-3 months. A negative antigen test indicates that at the time the sample was taken the cat did not have detectable levels of circulating FeLV antigen. Some cats can be latently infected and not demonstrate viremia.

FIP Antibody Titer

Titers < 128 are negative for antibody to feline coronavirus. Some young cats with acute or overwhelming infections do not have antibody titers.
Titers of 128-512 suggest vaccination or infection. One-third of cats with a post infection titer are shedding virus. A definitive diagnosis of clinical FIP cannot be made with titers of this magnitude. A follow up titer in 6 to 12 months should be made if it is a closed household or the cat is isolated.

Titer =/> 1024 Have been associated with clinical FIP. This prediction is reliable if the cat is from a solitary or closed household with no change in the last year. If the cat is from a multi cat or open household then it has been infected with feline coronavirus and the liklihood to develop disease cannot be determined. A follow up titer in 6 to 12 months should be made if it is a closed household or the cat is isolated.

FIV Antibody Test

A positive test result correlates with vaccination or an FIV infection. False negative titers are seen within 60-90 days of infection or very late in infection in cats with terminal immunosuppression.

G

Gender Determination PCR (Psittacines; contact IDL for other species)

See results report.

Generic circovirus in situ hybridization

Results report states sample is Positive or Negative.

Generic circovirus PCR

Results report states sample is Positive or Negative.

Generic Herpesvirus PCR

Results report states sample is Positive or Negative.

H

Hepatitis Panel in situ hybridization (Pacheco’s, Adenovirus, Polyomavirus)

Results report states sample is Positive or Negative for each test.

Herpesvirus (generic) PCR

Results report states sample is Positive or Negative.

Histopathology

See results report.

I

Immunohistochemistry tests

Results report states sample is Positive or Negative.

In situ hybridization tests

Results report states sample is Positive or Negative.

K

Koi Herpesvirus in situ hybridization

Results report states sample is Positive or Negative.

Koi Herpesvirus (PCR and virus isolation)

Results report states sample is either Positive or Negative and/or virus grew in culture.

L

Lyme Disease Antibody Titer

IgM titers < 1024 and IgG titers < 256 suggest that the animal has not mounted a detectable antibody response to Borrelia. Positive titers take 2-3 months to develop after infection and usually correlate with the onset of clinical illness.
IgM titers =/ >1024 and IgG titers < /=128 suggest recent exposure to Borrelia, although other spirochete infections (leptospirosis, GI spirochetosis) may cause cross-reactivity in IgM antibodies, but usually at lower dilutions.
IgM titers =/ >1024 and IgG titers =/ >256 are seropositive and usually correlate with clinical illness or vaccination.
IgM titers < 1024 and IgG titers =/>256 suggest infection with Borrelia or vaccination.

M

Microbial Culture and Sensitivity

See results report.

N

Necropsy (avian and small exotics; contact IDL for other species)

See results report.

Neospora caninum Antibody

Titers < /= 64 are negative for Neospora caninum. A titer of 128 indicates low levels of antibody to Neospora caninum. Since this is a borderline positive result, a recheck in 2 weeks is strongly recommended.
Titers =/ > 256 are positive for antibody to Neospora caninum. This is suggestive of an active infection.

Neospora caninum PCR

Results report states whether sample is Positive or Negative.

Nidovirus RT-PCR

Results report states sample is Positive or Negative, with or without endogenous RNA

O

Ophidian Paramyxovirus in situ hybridization

Results report states sample is Positive or Negative.

Ophidian Paramyxovirus RT-PCR

Results report states sample is Positive or Negative.

Ophidian Paramyxovirus Panel

Results report states sample is Positive or Negative for each test.

P

Pacheco’s Disease Virus in situ hybridization

Results report states sample is either Positive or Negative

Pacheco’s Disease Virus Results

As in the case for most viruses, the most effective way to control the continued spread of Pacheco’s disease is through vaccination.

DNA Probe Testing

DNA probe test is Positive: indicates that the target segment of Pacheco’s disease virus nucleic acid has been detected in the submitted sample.
DNA probe test is Negative: indicates that the target segment of Pacheco’s disease virus nucleic acid has not been detected in the submitted sample.
As a rule, psittacine birds infected with Pacheco’s disease virus will either die or will seroconvert and recover. The detection of Pacheco’s disease virus nucleic acid in any sample collected from a bird indicates a contaminated environment e.g. aviary, pet shop, home, plane, car to which the bird has recently been exposed. This warrants a search for the source of the virus.Isolation of a positive bird, vaccination of other birds exposed to the same contaminated environment, thorough and repeated cleaning/disinfecting and environmental testing are recommended to reduce the unabated spread of the virus.

Antibody Testing

As a rule, psittacine birds infected with Pacheco’s disease virus will either die or will seroconvert and recover. An assay to detect virus-neutralizing antibodies can be used to determine if a bird has been infected with Pacheco’s disease virus or has been successfully vaccinated. Demonstration of a rising titer in paired serum samples indicates a recent infection while a decreasing titer in paired serum samples indicates that the humoral immune system is no longer being stimulated. An antibody titer < 20 is considered negative, a titer >= 20 is considered positive. While the rate with which virus-neutralizing antibody levels decrease will vary with the individual, the detection of rising or high antibody titers suggests that a bird has recently been infected. This warrants a search for the source of the virus (aviary, pet shop, bird show, home, plane, car, etc.). Isolation of an actively infected bird, vaccination of other birds exposed to the same contaminated environment, thorough cleaning, disinfecting, and environmental testing are recommended to reduce the unabated spread of the virus. A bird with a Pacheco’s disease virus antibody titer should be considered latently infected.

Pasteurella multocida Antigen PCR

Results report states sample is either Positive or Negative for detection of Pasteurella multocida bacterial DNA.

Pasteurella multocida Antibody Titer

Results report states sample is Negative or gives numerical titer.
Titers >= 16 are considered seropositive

Pasteurella multocida Panel

Results report states Positive or Negative for detection of Pasteurella multocida bacterial DNA.
Results report states sample is Negative or gives numerical titer.
Titers >= 16 are considered seropositive

Psittacine Circovirus (PCV) Results

Until a safe subunit vaccine is available, testing of birds for the presence of psittacine circoviral nucleic acid followed by the isolation of persistently infected birds is the best method to reduce the spread of this virus among Psittaciformes. The PCV (formerly PBFD) virus assay uses viral specific nucleic acid primers and a probe to detect as few as 10 copies of a small segment of viral specific DNA in white blood cells, swabs of feather pulp or swabs of samples collected from a bird’s living area that may be contaminated with viral nucleic acid. The test can be used to detect target nucleic acid in the blood of birds with active disease (feather abnormalities are discernible), birds who are in the process of clearing an infection (nucleic acid is present in white blood cells in the absence of feather abnormalities) and in birds who are actively infected but have not yet developed obvious feather abnormalities. A positive test indicates that the target segment of PCV viral nucleic acid has been detected in the submitted sample. A negative test indicates that the target segment of PCV viral nucleic acid has not been detected in the submitted sample. A positive blood test in a bird with abnormally developing feathers (this must be differentiated from feather abnormalities that occur after the feather has matured) suggests that the bird is actively infected. A positive blood test in a bird that does not have feather abnormalities suggests that the bird may be clearing the virus from the body or that the bird is persistently infected and may develop feather abnormalities in the future. A bird that is positive with no feather abnormalities should be re-tested > 90 days after the initial test for PCV 1 and > 180 days after the initial test for PCV 2. The detection of PCV viral nucleic acid in the blood of a bird with no feather abnormalities indicates a virus-contaminated environment e.g. aviary, pet shop, home, plane, car to which the bird has recently been exposed. This warrants a search for the source of the virus.

Bird has abnormally developed or developing feathers:

DNA probe assay is Positive: Suggests Active Infection.
Management: If the bird is from a breeding aviary it should be removed and all areas that could be contaminated with feather dust from the infected bird should be repeatedly cleaned. Submitting swabs of the potentially contaminated environment can monitor cleaning efforts. If a companion bird is affected it should not be exposed to other birds outside of the household and one should be aware that the virus can be transported to other locations on ones clothes or in ones hair. It should be noted that, occasionally, some PCV virus-affected Psittaciformes of South American descent have spontaneously recovered from PCV 1 associated disease. Lories with PCV 2 associated disease may also recover.
DNA probe assay is Negative: A feather biopsy (including the feather follicle) should be submitted for histologic examination.

Bird Has Normally Developed Feathers:

DNA probe assay is Positive: Indicates that the bird has been exposed to PCV virus and that viral nucleic acid is present in the blood. The bird must be re-tested in > 90 days for PCV 1 and > 180 days after the initial test for PCV 2. If the bird is Negative when re-tested, it indicates that viral nucleic acid was not detectable in the blood. If the bird is still Positive, it indicates that the bird is either persistently infected or that the bird is being repeatedly exposed to the virus. It should be noted that most birds that are exposed to the PCV virus develop a transient infection followed by an appropriate immune response and recovery from the infection.
DNA probe assay is Negative: Indicates that PCV viral nucleic acid was not detected in the blood.

Psittacine Beak and Feather Disease Virus in situ hybridization

Results report states sample is Positive or Negative.

Porcine circovirus in situ hybridization: see generic circovirus in situ hybridization

Results report states sample is Positive or Negative.

Pigeon Circovirus

Results Report states whether sample is Positive or Negative.

R

Rheumatoid Factor (RF)

Synbiotics CRF Latex agglutination assay is used. A positive result indicates the presence of rheumatoid type antibodies. A negative result does not rule out the diagnosis of rheumatoid arthritis as RF may not be detected in 70% of dogs with rheumatoid arthritis.

RMSF Antibody Titer

IgM titers =/ > 16 are considered seropositive and compatible with a recent RMSF infection. A borderline positive of 16 should be rechecked in 2 weeks. An elevated IgM titer (=/ > 16) without presence of IgG suggests infection within the past 2-4 weeks.
IgG titers =/ > 64 are seropositive. Response to antibiotic therapy and type and duration of clinical signs should be considered in any assessment. A very high IgG titer (=/ > 512) along with the high IgM titer suggests recent or active infection. Elevated titers for both antibodies suggest infection occurred within the past 4-8 weeks.
IgM titers < /= 8 and IgG titers < 64 are seronegative for antibody to RMSF. If clinical signs have been present for < 2 weeks, there is the possibility of an early infection. We recommend a recheck sample in 2 weeks to verify a rising IgM and/or IgG titer.

IgM titers < /= 8 and IgG titers = 64- 256 suggest past infection. Some IgG titers at this level may persist for years. This also may represent an early infection. A four-fold or greater increase in the IgG titer on a recheck sample in 2 weeks indicates an active infection. Early antimicrobial therapy may reduce the peak antibody titers.
IgM titers < /= 8 and IgG titers =/ > 512 are compatible with a recent RMSF infection of between 2 weeks to 3 months duration. Since IgG titers of this magnitude rarely persist longer than 1 year, the dog was most likely infected this season.

S

Salmonella sp. (PCR, culture)

Results report states sample is Positive or Negative.

Sex Determination

See results report.

Salmonella spp. Antibody Screening

Results Report states: A titer of 1:10 or greater is considered a positive titer.

Salmonella spp. Antibody Titration

Agglutination assays inherently favor the detection of IgM, which the body develops during the early phase of an infection. To determine the clinical significance of a titer, a second titer needs to be determined in 2 to 3 weeks. When comparing titers, a rising titer of at least 2 dilutions is consistent with acute infection. A falling titer of at least 2 dilutions could indicate transition from an early phase IgM antibody response to a later phase IgG antibody response or that the bird has mounted an effective immunologic defense and is clearing the infection. PCR-based testing of a cloacal swab or feces will help to determine the state of infections. A constant titer suggests that the animal has been previously infected and mounted a detectable immune response.

Spironucleus

Results Report states whether sample is Positive or Negative.

T

Tick-borne Disease Panel

See individual tests (Rocky Mountain Spotted Fever, Lyme’s Disease and Ehrlichia canis) for interpretations.

Toxoplasma gondii Antibody Titer

IgM titers < 64 and IgG titers < 64 are negative for antibody to Toxoplasma gondii. In rare cases, a pre-acute infection may be present. If clinical signs are suggestive of toxoplasmosis, we recommend a recheck sample in 2 weeks to verify a rising IgM and/or IgG titer.

IgM titers =/ < 64 and IgG titers =/ > 64 indicate past Toxoplasma infection. Since only IgG is positive, the duration of infection may range from 6 months to several years. Rechecking a sample in 2 to 3 weeks will help clarify the state of infection if a 2-fold dilution or greater change in titer (increase or decrease) is observed. However, dogs with titers =/ > 1024 are more likely to have an active infection than dogs with lower titers.

IgM titers =/ > 64 indicate recent infection. Cases with IgM titers =/ >256 are more compatible with clinical toxoplasmosis. Titers < 256 should be rechecked in 2 – 3 weeks if clinical toxoplasmosis is still suspected. In some cases, cats may maintain an IgM titer < 256 for more than 6 months. Animals with chronic, encysted infections may also show a rise in IgM if the infection becomes reactivated and may be indicated by a titer for IgG =/ >64.