|
|
Clinical Pathology Laboratory - Available Test
|
|
Synovial Fluid Cytology Report
|
| |
| |
| An example of our synovial fluid report is indicated below. For
all synovial fluids, we perform the following: |
-
Visual assessment: Color, turbidity, volume.
Viscosity: This is estimated visually.
Cell counts: This includes both red and white blood
cell counts. This is done manually using our bench top impedance
counter, the Coulter Z2. Results are reported out as thousands
of cells/µL. Because synovial fluids are quite viscous
(and can gel completely), in some cases, we add hyaluronic
acid to the fluid to enable us to do cell counts and make
smears. The normal nucleated cell count is species- and joint-dependent.
In healthy dogs and cats, joint fluids have < 3.0 thous/µL
nucleated cell counts, with little blood. The nucleated cell
count in healthy equine synovial fluids is < 1.0 thous/µL.
Total protein: This is measured by refractometer. Normal
joint fluids have < 2.5 g/dL of protein.
Cytologic evaluation: The type of smear made depends
on the cellularity of the fluid. For joint fluids, we either
do direct or sediment smears because the fluid is too viscous
for cytospin smears. In all species, mononuclear cells (lymphocytes,
macrophages) dominate in synovial fluid, with < 10% neutrophils.
It is quite uncommon to see bacteria in septic arthritides
(the image shown above is actually an exceptional fluid).
|
| |
Joint fluid cytology from a foal with septic arthritis. There are
large numbers of degenerate neutrophils with intracellular bacterial
cocci. |
| |
| Joint fluids are generally stable for up to 24 hours after collection,
if refrigerated. Some changes will occur in vitro, such as phagocytosis
of erythrocytes and bacteria. This complicates result interpretation,
so freshly made smears (direct or sediment) should be provided with
the fluid when sample submission is delayed. If this is done, please
specify the type of smear made, i.e. direct or sediment, on the request
form. If a sediment smear is made, leave at least 1 ml of fluid uncentrifuged,
in order to allow us to perform accurate cell counts. |
|
|
|
