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2. Chapter Outline
Physiology and Composition of Synovial Fluid
Specimen Collection
Laboratory Testing
Macroscopic Evaluation
Chemical Examination
Microscopic Examination
Classification of Joint Disorders

3. Synovial Fluid
Synovial
syn(like) + ovia (egg)
“Joint Fluid”

4. Synovial Fluid
Viscous fluid found in the
cavities of movable joints
(diarthroses)
Synovial membrane
Inner membrane of
synovial joints
Secretes synovial fluid
into the joint cavity
Contain specialized cells
(synoviocytes)

5. Composition
Hyaluronic acid
synthesized by the synovial membrane
increase the viscosity and elasticity of articular
cartilages
lubricate the surface between synovium and
cartilage.
Lubricin secreted by synovial cells.
It is chiefly responsible for so called boundary
layer lubrication, which reduces friction between
opposing surfaces of cartilage.

6. What do you call the damage
to the articular membranes
producing stiffness and pain in
the joints?

8. Major Functions
Reducing friction
Lubrication
Lessen shock
Supplying oxygen and
nutrients

11. Synovial Fluid:
Specimen Collection

12. Bulge test
The Bulge test is used to determine if there is an
abnormal amount of fluid surrounding a joint
Bulge test of joint for the detection of synovial effusion

13. Bulge Test

14. Specimen Collection
Arthrocentesis
Placement of needle in arthrocentesis of (A) elbow and
(B) knee joints.

15. Macroscopic Laboratory
Testing
Volume
Color and Clarity
Inclusions
Viscosity
Clotting
Mucin Clot

16. Laboratory Testing: Macroscopic
Volume
Normal up to <3.5 ml of fluid
Can reach up to 25 ml
Inflammation

17. Macroscopic Analysis: Color and Clarity
Colorless to pale yellow and clear
normal
Red, brown, or xanthochromic
 hemorrhage into the joint
Yellow/clear
noninflammatory effusions
Yellow/cloudy
inflammation
White/cloudy/milky
Crystals
Deeper yellow
Non inflammatory and inflammatory effusions

18. Macroscopic Analysis: Inclusions
Rice bodies.
Free-floating aggregates of tissue appear as
rice bodies.
rheumatoid arthritis (RA)
Degenarated synovium enriched with
fibrin
Ochronotic shards
debris from joint prosthesis
look like ground pepper
A =ochronotic shards
B =rice bodies

19. Macroscopic Analysis: Viscosity
“Ropes” or “Mucin
Clot Test”
Normal = 4-6 cm
When 2-5% acetic acid
is added, normal
synovial fluid will form
a clot surrounded by
clear fluid

20. A medical technologist received 2 clear,
thick and viscous samples labelled A
and B. He added 2% acetic acid, sample
A did not clot while sample B did.
Which of the following is suggestive of
synovial fluid? The other sample may
possibly be?

21. When sufficient blood is collected,
it should be distributed in what
color of tubes?

22. Sterile heparinized = GS/CS
Heparin / EDTA = cell count
Noncoagulated tube = other tests
Sodium fluoride = Glucose

23. Macroscopic Analysis: Clotting
Normal synovial fluid: Do not clot
Clotting of synovial fluid = fibrinogen
1.Damaged synovial membrane
2.Traumatic tap

24. Macroscopic Analysis: Mucin Clot
“Ropes test”
Estimation of hyaluronic acid–
protein complex integrity
The adding of acetic acid to
normal synovial fluid, which
causes clot formation.
Criteria:
Compactness of the clot
Clarity of the supernatant fluid

25. Mucin Test
Good : solid clot
Fair: soft clot
Low: Friable clot
Poor: No clot

26. Macroscopic Analysis: Cell Counts
Total leukocyte count
<200 cells/uL
Very viscous fluid
Pinch of hyaluronidase + 0.5 ml fluid
1 gtt 0.05% hyaluronidase in phosphate buffer per ml of
fluid (incubate 37oC for 5 minutes)

27. Macroscopic Analysis: Cell Counts
Diluents:
Saline
0.3% hypotonic solution
Saline that contains saponin

28. Why is the traditional WBC
fluid not used for cell counting?

29. Because it contains
______________ which is
responsible for clotting.

30. Can clear undiluted fluid be
used for counting?

31. Macroscopic Analysis: Cell
Counts
Neubauer Counting Chamber

32. Macroscopic Analysis: Diff Count
Incubate with hyaluronidase
Neutrophils : <25% of the differential
Lymphocytes: <15%
Crystal: None present
Increase neutrophil: septic condition
Increase cell count with increase lymphocyte:
nonseptic inflammation

33. Chemical Analysis: Protein
All proteins found in plasma
Exception: various high–molecular weight
proteins which may be present in very small
amount
Fibrinogen
beta 2 macroglobulin
alpha 2 macroglobulin
Use common serum protein procedures

34. Chemical Analysis: Protein (cont.)
Normal range <3 g/dl
Increased protein
ankylosing spondylitis
arthritis
Crohn disease
Gout
Psoriasis
Reiter syndrome
ulcerative colitis.

35. Chemical Analysis: Glucose
Compare to serum glucose levels
<10 mg/dL lower than blood glucose
Decreased – joint disorders
>20mg/dl decrease - infection

36. Chemical Analysis: Uric Acid
Normal - 6 to 8 mg/dL
Increased – gout
May form crystals

37. Chemical Analysis: Lactic Acid
Rarely measured in synovial fluid
Can be helpful in diagnosing septic arthritis.
Normal = less than 25 mg/dL
Septic arthritis can show levels up to 1000 mg/dL

38. Laboratory Testing: Lactate Dehydrogenase
Elevated in synovial fluid
Normal in serum level
Increased in
Rheumatoid arthritis
(RA)
infectious arthritis
gout
Neutrophils increased
during the acute phase of
these disorders contribute
to this increased LD.

39. Laboratory Testing: Rheumatoid Factor
RF is an antibody to immunoglobulins.
Present in rheumatoid arthritis:
Serum – most cases
Synovial fluid - 50%
Rarely elevated only in synovial fluid and not
serum
False positives in other chronic inflammatory
diseases.

40. Microscopic Analysis: Differential
LE cells
Neutrophils that have
engulfed a nucleus of
a lymphocyte
Tart cells
Monocytes that have
engulfed nuclear
material

41. Microscopic Analysis: Differential
Reiter cells
Vacuolated macrophages
with ingested neutrophils
RA cells
“Ragocytes”
Neutrophils with small,
dark, cytoplasmic
granules that consist of
precipitated rheumatoid
factor

42. Microscopic Analysis: Differential
Hemosiderin
Seen in Pigmented
Villonodular Synovitis
Inclusions within clusters
of synovial cells
Rice bodies
Macroscopically resemble
polished rice
Macroscopically show
collagen and fibrin

43. Microscopic Analysis: Differential
Fat droplets
Refractile intracellular and
extracellular globules
Stain with Sudan Dye

44. Crystal Identification
Monosodium urate (MSU)
Calcium pyrophosphate (CPPD)

45. Crystal Identification
Corticosteroid
Cholesterol

46. Crystal Identification
Calcium oxalate
Apatite (Ca Phosphate)

47. Laboratory Testing: Microbiology
Staining
Smears prepared by centrifugation or
cytocentrifugation
Saline dilution reduces clustering of cells
Gram’s stain most common
Culture
Set up with positive or negative stain results
Aerobic
anaerobic

48. Classification of Joint Disorders

49. Classification of Joint Disorders
Group Classification Pathologic Significance
1. Noninflammatory Degenerative joint
disorders, osteoarthritis
2. Inflammatory Immunologic Disorders,
RA, LE, Scleroderma,
Polymyositis, ankylylosing
spondylitis, rheumatic
fever, Lyme arthritis,
Crystal-induced gout,
pseudogout

50. Classification of Joint Disorders
3. Septic Microbial Infection
4. Hemorrhagic Traumatic injury, tumors,
hemophilia, other coagulation
disorders, anticoagulant overdose

51. Laboratory Findings
1. Noninflammatory
Clear, yellow fluid
Good viscosity
WBCs <1000 uL
Neutrophils <30%
Normal glucose (similar to blood glucose)

52. Laboratory Findings
2. Inflammatory
Immunologic origin Crystal - induced
 Cloudy, yellow fluid Cloudy, yellow fluid
 Poor viscosity Low viscosity
 WBCs 2,000 – 75,000 uL up to 100,000 uL
 Neutrophils >50% <70%
 Decrease glucose level Decreased glucose level
 autoantibodies present Crystals present

53. Laboratory Findings
3. Septic
Cloudy yellow-green fluid
Variable viscosity
WBCs 50,000 – 100,000 uL
Neutrophils > 75%
Decreased glucose level
Positive culture and gram stain

54. Laboratory Findings
4. Hemorrhagic
Cloudy, red fluid
Low viscosity
WBCs equal to blood
Neutrophils equal to blood
Normal Glucose level

55. Review of Key Points
Synovial fluid analysis
Is a well-established procedure for evaluation of joint
disease.
Determines the presence of arthritis
Assists in the classification of joint disorders
Helps guides appropriate treatments

56. Thank you