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PARR FAQ's

Can you run PARR on formalin fixed / paraffin embedded samples or cover-slipped slides?

No, we cannot run PARR on formalin fixed, paraffin embedded samples or slides that have cover-slips glued to them.
 

Can you run PARR on stained slides?

Yes, we can run PARR on stained slides.
 

Does a negative PARR result rule out lymphoma?

No. We estimate we detect 75% of confirmed canine lymphomas with the PARR assay. We estimate we detect 65% of confirmed feline lymphoma cases with the PARR assay. Therefore, a negative result does not rule out the diagnosis of lymphoma in either species.
 

What species can you test?

Canine and feline patients only.
 

How do I pack/ship samples to the lab?

  1. Send samples for flow cytometry overnight, on ice. DO NOT FREEZE! We do not recommend sending samples for flow cytometry for weekend delivery. We are open Monday through Friday, and the cell viability can decrease while the sample sits over the weekend.
  2. Samples for PARR testing do not need to be sent on ice, and can be sent standard mail or overnight, depending on how quickly you would like results.
  3. Specific instructions and shipping addresses can be found on the Shipping Instructions Webpage

What is the sensitivity and specificity of the PARR and flow cytometry test?

  1. We estimate that in dogs, the PARR assay is 94% specific for lymphoid neoplasia, and the sensitivity is 75%.
  2. We estimate that in cats, the PARR assay has similar specificity to dogs (greater than 90%). In cats, the sensitivity of the PARR assay is estimated to be about 65%.
  3. Flow cytometry is an interpretive test. Therefore, we do not have sensitivity and specificity values for this diagnostic test.

How much CSF should I send for PARR?

We need a minimum of 50,000 WBC for PARR. Most labs will report the WBC counts as # of cells/microliter. Take 50,000 and divide by #cells/microliter. This will give you the minimum amount of CSF needed in microliters.
 

How much blood should I send for the PARR and/or flow cytometry?

  1. Please send one purple top tube for PARR. We need a minimum of 100 microliters of blood.
  2. Please send at least 0.5 ml of blood for flow cytometry. Please send an additional purple top tube if you would like to have a CBC completed at CSU.
  3. See the PARR Submission Instructions for more details

Can I forward slides from another lab?

Yes, please be sure to have them send a sample submission form with the slides!
 

What is the difference between flow cytometry and PARR?

  1. The PARR assay is a PCR assay in which we are amplifying DNA. The results tell us if the majority of cells in the sample are derived from the same original clone (most consistent with neoplasia), or from multiple clones (most consistent with a reactive process). Here is a review of this methodology, "Molecular diagnostics of hematologic malignancies".
  2. The flow cytometry study involves staining live cells with labeled antibodies that bind to proteins expressed on the cell surface. Different types of lymphocytes express different protein (for example T cells express the protein CD3, and B cells express the protein CD21). The cells are analyzed on a flow cytometer, which tells us how many cells of each type are present. This information allows us to determine the lineage of the cells present, and whether they are homogeneous (more consistent with neoplasia) or heterogeneous (more consistent with a reactive process). Workman et al (Vet Clinics Small Animal 2003, 1379 – 1399) contains additional information about this assay.

Can PARR be used as an early detector for patients coming out of remission?

We do not have data supporting the use of PARR as an early detector. Theoretically, however, if the patient had a positive PARR result in the past, PARR may be used as an early detector of recurrence, but this is a topic of ongoing studies.