Cell Count, Synovial Fluid

Useful For

Synovial fluid is basically an ultrafiltrate of plasma combined with a mucopolysaccharide (hyaluronate) that is synthesized by the cells of the synovial membrane. The functions of the synovial fluid are to lubricate the joint space and transport nutrients to the articular cartilage. Various disorders produce changes in the chemical constituents of the joint fluid and in the type of cell population present. The five major disease categories are non-inflammatory, inflammatory, infectious, crystal-associated, and hemorrhagic.

Method Name

Manual or Impedance Count

Aliases

Cell Count, Synovial Fluid; Joint Fluid; Crystals, Cell Count - Synovial Fluid

Specimen Type

Specimens should be collected in EDTA tubes. Examination for crystals should be carried out as soon as possible as false positive or negative results may result. Total cell counts should be performed within 4 hours of collection. If the specimen cannot be tested immediately, refrigeration will help to maintain morphologic features for smears for up to 24 hours.

Specimen Required

One lavender top (EDTA) tube.

Specimen Minimum Volume

0.5 mL of fluid

Specimen Stability Information

4 hours at room temperature or 24 hours refrigerated.

Rejected Due To

  • Clotted
  • >4 hours old and has not been refrigerated.
  • <0.5 mL submitted.

Special Instructions

Cell counts cannot be performed on clotted fluids.

Performing Laboratory

As ordered. Turn around time is 4 hours.

Reference Values

See report

Day(s) and Time(s) Performed

Monday – Friday, 24 hours/day

Analytical Time

1-2 hours

Specimen Retention Time

2 days

CPT Code Information

89051, 89060

Analytical Time

1-2 hours