Synovial Fluid Analysis

Question 1

composition of synovial fluid

Answer 1

formed as an ultrafiltrate of plasma across the synovial membrane
mucopolysaccaride containing hyaluronic acid & a small amount of protein secreted by synoviocytes

Question 2

function of synovial fluid

Answer 2

supply nutrients to cartilage

lubricant to surfaces of frequently moving joints

Question 3

noninflammatory

Answer 3

degenerative joint disorders

osteoarthritis

Question 4

inflammatory

Answer 4

immunological disordres
RA, SLE
crystal induced: gout & pseudogout

Question 5

Septic

Answer 5

infection- bacterial, tubercular, fungal

Question 6

Hemorrhagic

Answer 6

traumatic injury
hemophilia
coagulation disorders
anticoagulant overdose

Question 7

collection

Answer 7

arthrocentesis (if possible fasting 4-6 hours)
blood sample collected at same time
3 tubes collected

Question 8

3 tubes collected

Answer 8

1: non-anticoagulated tube - chemical & immunological
2. anticoagulated (Naheparin/liquid EDTA)- hematology
3. sterile (Na heparin/SPS) microbiology

Question 9

transport & analysis

Answer 9

room temp

evaluate immedately

Question 10

most helpful analysis on synovial fluid

Answer 10

WBC & differential

gram stain, culture & crystal examination

Question 11

mucin clot test

Answer 11

performed if there are any concerns that fluid sample is not synovial fluid
normal synovial fluid shouldn’t have fibrinogen & doesn’t clot
dilute w/ 2% acetic acid- hyaluronate from joint will form a clot in acid

Question 12

normal color & clarity

Answer 12

clear, pale yellow

Question 13

yellow color/clarity

Answer 13

inflammation

Question 14

greenish color/clarity

Answer 14

bacterial infection

Question 15

bloody color/clarity

Answer 15

hemorrhagic arthritis/traumatic tap; joint fractures; tumors

Question 16

milky color/clarity

Answer 16

SLE, tuberculous arthritis

Question 17

substances that can affect synovial fluid clarity

Answer 17

WBCs, RBCs, & synoviocytes
crystals, fat droplets
fibrin, cellular debris, rice bodies

Question 18

rice bodies

Answer 18

white, free-floating substances made up of collagen covered by fibrinous tissue; resemble polished, shiny grains of rice of various sizes; seen most commonly in rheumatoid arthritis

Question 19

viscosity during inflammation

Answer 19

hyaluronate can be depolymerized by enzyme hyaluronidase present in bacteria & some neutrophils

Question 20

severe inflammation in synovial fluid

Answer 20

> 100,000 WBC/ul

pre-treatment w/ hyaluronidase permits proper mixing & accurate cell counts

Question 21

increase in neutrophils

Answer 21

septic

Question 22

increase in lymphocytes

Answer 22

non-septic inflammation

Question 23

abnormal cells in synovial fluid

Answer 23

eosinophils
LE cells
reiter cells
RA cells (ragocytes)
malignant cells
lipids
hemosiderin granules

Question 24

crystal ID

Answer 24

important microscopic exam

polarized microscopy

Question 25

monosodium urate crystals

Answer 25

present in gouty arthritis
needle-like crystals w/ pointed ends
polarized :
strongly negative birefringent (bright against black background)
appear yellow when longitudinal axes are parallel to it & blue when perpendicular

Question 26

Calcium pyrophosphate dihydrate crystals

Answer 26

degenerative arthritis
smaller & blunter than urate crystals
rodlike or rhomboid; display weak positive birefringence w/ their colors opposite of that to urate with red compensator

Question 27

other crystals

Answer 27

cholesterol
hydroxyapatite
corticosteroids

Question 28

glucose

Answer 28

not more than 10 mg/dl lower than blood

marked decrease: inflammatory or septic disorders

Question 29

bacteria in synovial fluids

Answer 29

neisseria gonorrheae

staphylococcus aureus