Urinalysis and Body Fluids 6th Edition by Majorie DiLorenzo, Susan Strasinger

Exercise 1

A 50-year-old man presents in the emergency department with severe pain and swelling in the right knee. Arthrocentesis is performed and 20 mL of milky synovial fluid is collected. The physician orders a Gram stain, culture, and crystal examination of the fluid, as well as a serum uric acid. She requests that the synovial fluid be saved for possible additional tests.

a. Describe the tubes into which the fluid would be routinely placed.

b. If the patient’s serum uric acid level is elevated, what type of crystals and disorder are probable?

c. Describe the appearance of these crystals under direct and compensated polarized light.

d. Why were the Gram stain and culture ordered?

Step 1 of 4

a.

Synovial fluid tests using tubes:

The following are the routinely used tubes to perform laboratory tests on synovial fluid.

Sterile heparinized or sodium polyanethol sulfonate:

• It is a appropriate collection tube to determine presence of gram stain, and to perform culture test

Heparin or liquid EDTA ( ethylenediaminetetraacetic acid):

• It is a appropriate collection tube to get the cell count in the synovial fluid

Nonanticoagulated:

• It is a appropriate collection tube analyze all the other tests such as crystal formation examination and differential count in the synovial fluid