SYNOVIAL FLUID ANALYSIS

• Also known as “joint fluid”, from the latin word “egg white”

  SYNOVIAL FLUID ANALYSIS
• SYNOVIAL FLUID ANALYSIS from the latin word “egg white”
• Synovial fluid is produced as an ultrafiltrate of blood plasma
• Fluid circulating in the diarthroses/ movable joints (full movement)
• SYNOVIAL FLUID ANALYSIS Method of collection:

  ARTHROCENTESIS
• (aka joint aspiration, needle is use to take fluid out of the joint)

  ARTHROCENTESIS
• Phagocytic cells in the synovial membrane =

  synoviocytes
• Phagocytic cells in the synovial membrane = synoviocytes – hyaluronic fluid = viscosity
• (thick,sticky consistency between solid and liquid)

  hyaluronic fluid
• is a natural substance found in the fluids in the eyes and joints.

  Hyaluronic acid
• Hyaluronic acid is a natural substance found in the fluids in the eyes and joints
• acts as a cushion and lubricant in the joints and other tissues.

  Hyaluronic acid
• Different forms of hyaluronic acid are used for cosmetic

  purposes.

  Hyaluronic acid
• might also affect the way the body responds to injury and help to decrease swelling.

  Hyaluronic acid
• They are synovial intimal cells,located in the inner surface of joint cavity and are responsible for the production of synovial fluid components and removing debris in synovial fluid as phagocytic cell.

  synoviocytes
• Specimen Collection

  • Fluid is usually collected in a syringe that has been moistened by heparin
• for glucose analysis = sodium fluoride
• In 1940s sodium fluoride (NaF) containing tubes were introduced into laboratory practice for blood collection for glucose measurement.
• In 1940s sodium fluoride (NaF) containing tubes were introduced into laboratory practice for blood collection for glucose measurement.
• Tube 1 : Microbiology (3-5 ml in sterile tube), add 25 U heparin / mL fluid
• Tube 2 : Hematology (3-5 ml fluid, add 25 U heparin / mL fluid)
• Tube 2 : Hematology

  do not use crystalline EDTA, but liquid EDTA may be accepted
• Tube 3 : Chemistry (3-5 ml in red top tube and observe for clotting)
• Tube 1

  Microbiology
• Tube 2

  Hematology
• Tube 3

  Chemistry
• Clotting indicates leakage of fibrinogen from the circulation, and is a non-specific abnormal finding that may also be caused by a traumatic tap
• Normal synovial fluid does not clot
• Fluid from a diseased joint may contain fibrinogen and will clot
• Normal Values of Synovial Fluid:

  Volume : less than 3.5 ml

  Color : pale yellow

  Clarity : clear (turbid = (+) WBC ; milky = (+) crystals)

  Viscosity : able to form a string 4-6cm long

  Crystals : absent
• Glucose : less than 10 mg/dl, lower than the blood glucose

  Lactate : less than 250 mg/dl

  Total Protein : less than 3 g/dL

  Uric acid ` : equal to blood value

  RBC count : less than 2,000 cells / uL

  WBC count : less than 200 cells/ uL

  Neutrophils : less than 20% of the differential

  Lymphocytes : less than 15% of the differential

  Monocytes & Macrophages: 65% of the differential
• Measurement of the degree of hyaluronate polymerization

  Rope’s Test / Mucin Clot test
• Rope’s Test / Mucin Clot test Reagent:

  2-5% acetic acid
• -The mucin clot test is a semiquantitative indicator of the amount of hyaluronic acid content based on acid precipitation.
• are hydrophilic molecules essential for the homeostasis of wet-surfaced epithelia, mucins could` play multiple roles in the protection of mucosal surfaces.

  Mucins
• Gel-forming mucins are essential for lubrication and clearance of allergens, pathogens and debris.
• Grades/ Report:

  * Good – solid clot

  * Fair – soft clot

  * Poor – friable clot

  *Very poor – no clot at all
• In arthritis, the viscosity of synovial fluid is decreased because of decreased production and polymerization of hyaluronic acid.
• Viscosity can be empirically evaluated by forming a string of synovial

  fluid between the tips of the fingers.
• In arthritis, the viscosity of synovial fluid is decreased because of decreased production and polymerization of hyaluronic acid.

  String test of synovial fluid