Submission Guidelines

AVL provides separate histopathology/cytology submission forms.

Forms should include the following information:
1) Name, age, species, gender, breed.
2) Clinical history including any laboratory findings.
3) Type of tissue being submitted; source.
4) Number of biopsies submitted
5) Any pending testing which might be relevant to diagnosis: Autoimmune testing, microbiology, etc.
6)  If you have specific questions, are concerned about a possible disease process, or have a list of differentials you would like to rule out, please indicate such.


Submit tissue in a leak proof container containing 10% formalin. Ratio of formalin to tissue is important; approximately four times volume of formalin to tissue is recommended.

Specimens can be held to fix (at least 24 hours) at your clinic prior to sending to the lab, especially larger tissue samples. Shipping large volumes of formalin can be hazardous and can incur fines if there is leakage! Once the tissue is fixed, wrap in wet paper towel (water only) and place in a double Ziploc bag (Please label).

Large tissues should be sectioned to allow adequate fixation.  Bread loafing (incomplete parallel cuts at a minimum of 2cm apart) can be performed on large specimens (BE SURE TO AVOID complete transection or too many cuts which can both result in loss of tissue orientation).

Specimens should be submitted in separate containers where multiple biopsies from various sites are taken. Example: do not submit small tissue fragments or endoscopic biopsies in the same container with larger tissues.  Fresh tissue samples should NEVER be larger than the narrowest portion of the jar. While fresh tissue is malleable and can be manipulated to fit into a container, upon fixation the tissue becomes “rigid” and can be difficult to remove.

Remember to clearly label containers to match information provided on test requests: patient name/source. DO NOT place tape of any kind around the formalin jars, this is NOT leak proof! Parafilm is required around the rim of a leak proof container when submitting samples.  Paperwork should be placed in a separate plastic bag to avoid contact with formalin if leaking does occur.

Never allow tissues or containers to freeze.

**Note: Samples of bone may require additional time due to decalcification procedures prior to processing and sectioning into tissues.


Complete histopathology/cytology submission form.

History is very important including any pertinent laboratory tests or pending tests.

Previous treatments, cytologic or histologic evaluations should be noted. Indicate source of FNA or fluid.

FNA: Submit air dried smears, at least two per site. Unstained slides are preferred.

Fluid Analysis

Submit both EDTA tube and plain red top tube of fluid. Please submit smears from both tubes. Preparing slides immediately after collection ensures the best results. Cellular morphology of samples collected in EDTA is only preserved for a day or two, those collected without EDTA fair worse.  Cytological morphology, cell counts and protein will be altered due to cell deterioration and such deterioration can significantly alter the accuracy of interpretation. Smears of sediment fluid are also recommended but not essential. Please indicate the sample source and whether the film is a direct or concentrated preparation.


DO NOT submit smears in same bag as biopsy specimens. Formalin vapors will adversely affect cellular morphology of cytology specimens.


338         Cytology Fluid Analysis  364         Histology 1 site
339         Cytology FNA 1 site  364A      Histology 2 sites
339A      Cytology FNA 2 sites  364B      Histology 3 sites
339B      Cytology FNA 3 sites  364C     Histology 4 sites
339C      Cytology Lymph Nodes  2-4 364D     Histology 5 sites
  364E     Histology 6 sites
  364F     Histology 7 sites