Specimen Requirements

CSF:
1. Gross Examination—Color and Clarity
2. Perform counts within 30 minutes after fluid collection. It has been found that 40% of NUCLEATED CELLS's will lyse after two hours at room temperature giving a false impression of the number of NUCLEATED CELLS's present. It is therefore, recommended that if a delay is anticipated, the specimen should be refrigerated.
3. Three or four aliquots of CSF specimen may be collected at the time of the procedure. If there is no designation for testing order, the following is recommended by CLSI (NCCLS) and most literature for body fluid testing:
▪ TUBE #1: Protein, glucose, other serologic tests or chemistries; if traumatic tap is suspected, a cell count should also be performed on Tube #1.
▪ TUBE #2: Gram stain and cultures
▪ TUBE #3: Cell Count and Differential
▪ TUBE #4: Other tests as required (e.g., cytology)

SEROUS FLUID:
1. Serous fluid from large volume collections may be aliquoted into smaller volumes BEFORE transport to the laboratory. Specimens should be gently agitated during collection, before aliquoting, and before testing for cell counts and diffs.
2. EDTA is the recommended anticoagulant for cell counts and diffs. Refrigerated storage is adequate for cell counts and diffs for up to 24 hours only if the fluid has been transported to the testing lab as soon as possible after the completion of the collection procedure, otherwise, cell lysis, cellular degradation and bacterial growth could occur and affect test results.

SYNOVIAL FLUID:
Synovial fluids may be transported and analyzed at room temperature. Some texts indicate that lithium heparin and EDTA should not be used as anticoagulants because they produce crystalline material that can be confused with pathologic crystals. However, others have used lithium heparin and EDTA without difficulty. Oxalate should not be used because of extensive formation of calcium oxalate crystals.