palpate bony landmarks to find insertion point between bones
attach needle to syringe and advance needle into joint space ("pop")
aspirate with gentle suction
3-4 samples from normal and abnormal joints
arthrocentesis results (normal)
normal joint fluid is sticky, few erythrocytes, 90% mononuclear cells and 5% neutrophils with "rowing"
Look at volume, color (clear to slight yellow), turbidity (should be clear), viscosity (hyaluronic acid), cellularity, cell distribution (rowing due to viscosity), protein concentration with refractometer
"through the needle" catheter with needle guard, lidocaine, hemostat, sterile gloces, syringes with non-bacteriostatic saline
transtracheal wash procedure
needle inserted bevel down into trachea until "pop" (cough or swallow)
catheter advanced through needle, withdraw needle, use needle guard.
stabilize with hemostat, inject warm sterile saline
aspirate fluid back into syringe
repeat until mucoid or purulent material are recovered
red top and EDTA tube, make smears and cultures
LIGHT sedation so they can cough/swallow
transtracheal wash results
normal: few cells, small mucus, epithelial cells primarily (columnar ciliated or nonciliated cuboidal), neutrophils, lymphocytes, eosinophils, plasma cells, mast cells and erythrocytes rarely, alveolar macrophages most common
abnormal: exudate, cellular with mucus, neutrophils in acute inflammation, mononuclear macrophages in chronic inflammation, maybe bacteria or fungal, eosinophils in allergic or parasitic, neoplasitc or erythrocytes possible
evaluates tissue architecture, observe in relation to neighboring cells
preparation of a sample involves several complex steps and some specialized equipment
first step is tissue biopsy
several different techniques
samples fixed in 10% neutral phosphate-buffered formalin
Place tissue in formalin, use cassette for small samples
disposable punches of various sizes, may or may not need sutures.
Fast and easy
rotate punch until tissue is sectioned, pull out or flush out onto tongue depressor, let dry then put depressor into formalin jar.
obtained with scalpel, near edge of lesion, want lesion, transitional and normal tissue in sample.
large and variably sized. Good for solitary lesions (mass)
No "tox screen", need history to know what to look for.
contact lab for appropriate procedure.
Can be whole blood, serum, vomit, gastric lavage, feces, urine in live animal
whole blood, serum, urine, gut contents, organs or tissues in necropsy