The Simpson Lab performs Fluorescent In-Situ Hybridization (FISH) diagnostic testing. This page contains information on submitting samples for FISH testing and an FAQ section for information on this type of testing.
Please complete the FISH Test Submission Form. Mail the FISH Form with the tissues you would like diagnosed. Payment must be made using our secure Online Payment Form. Payment must be received PRIOR to processing.
For further inquiry, please contact the lab at firstname.lastname@example.org and specify 'FISH Testing Inquiry' in the subject line.
What is FISH?
What are the indications for doing FISH?
FISH analysis of colonic biopsies is a vital adjunct to the diagnosis of Boxer dog colitis, in order to assess colon biopsies for evidence of intramucosal and intracellular bacterial invasion. If bacterial invasion is present, the invading species is usually E. coli, and we use a specific probe to detect E. coli infection. Diagnosis of bacterial invasion helps to formulate a treatment plan, in conjunction with colon culture and antimicrobial susceptibility data. It is important to appreciate that colon culture alone by no means confirms E. coli invasion, and for maximal diagnostic yield, culture data must crucially be interpreted alongside FISH for spatial localization of bacteria.
FISH can also be very helpful in clinical cases where where bacterial involvement is suspected based on clinical or histological evidence, for example in chronic granulomatous diseases, cholangiohepatitis, endocarditis, suppurative pancreatitis, pyelonephritis, lymphadenitis, chronic cystitis.
I have already taken biopsies, can I still submit FISH?
Yes. We do not require biopsies to be taken into special media for FISH analysis alone. We need a minimum of 5 unstained paraffinised sections, 4-5 microns thick, on charged glass slides.
If, however, you have not already taken biopsies it may be helpful to contact us for advice.
Can my regular histology lab do FISH?
Why not just do a Gram stain?
What are the limitations of FISH?
A negative FISH result does not completely exclude bacterial infection. Reasons for false negatives include the presence of dead/dying bacteria (they must be alive and metabolically active to take up the probe), low bacterial number, a patchy distribution of infection, overfixation, sulfasalazine treatment, and the presence of bacteria with thick cell walls (e.g. Listeria).
The eubacterial probe identifies most bacteria, and FISH MAY enable identification of the bacterial species present if we have the appropriate probe (though we have a limited # of species specific probes). It also does not provide any information on antimicrobial sensitivities.
False positives on FISH are also possible but unlikely, since we use additional probes as positive and negative controls.