synovial fluid

arthrocentesis

joint fluid aspiration

sterile, heparinized (green)

tube type for micro analysis of fluid

EDTA (purple)

anticoag in hematology analysis

non-anticoag (red/yellow)

tube type for glucose analysis of fluid

normal

colorless, pale yellow fluid is normal/abnormal

inflammation

indicated by yellow-white fluid color

red to brown

color of fluid in hemorrhagic event (can timeline)

pink, red

color of fluid in traumatic collection

yellow-green

color of septic fluid

xanthochromia (yellow)

color of fluid after centrifugation when blood present for long enough for hgb breakdown to bilirubin

crystals

presence indicated by milky fluid

rice bodies

-cartilage fragments in fluid

-seen with RA 

-indicative of inflammation

ochronotic shards

-brown fragments in fluid in alkaptonuria

-tyrosine and homogentisic acid buildup

-indicative of inflammation

viscosity

tested by string test

-measures polymerization of hyaluronic acid

dec

viscosity is inc/dec in RA

absent

viscosity in inflammation, sepsis, crystals, hemorrhage

synoviocyte

damage/death to these cells dec hyaluronic acid production and dec viscosity

hyaluronic acid

-synthesized by synoviocytes

-contribute to viscosity

mucin clot test

acetic acid added to synovial fluid to induce precipitation

poor

clot formation is strong/poor in inflammatory conditions

acetic acid

decreases pH to induce precipitation of synovial fluid in mucin clot test

lymphocytes

cell presence inc indicates non-septic inflammation

monocytes, macrophages

predominant cells in synovial fluid

neutrophils

cell type presence indicative of infection/sepsis

A

-synovial cell type

-macorophage-like

-phagocytic

B

-synovial cell type

-fibroblast-like

-secretory

sodium urate (MSU)

-gout crystals

-neg biref

-needle-like

-inc uric acid 

-intra/extra cellular

neg (yellow)

birefringence of MSU crystals is pos/neg (yellow/blue)

pos (blue)

birefringence of CPPD cyrstals is pos/neg (yellow/blue)

calcium pyrophosphate (CPPD)

-pseudogout crystals

-pos biref

-rhombic

-intra/extra cellular

tophus

nodular mass of MSU crystals

cholesterol

-extracellular crystals

-notched rhombic plates

-neg biref

neg (yellow)

biref of cholesterol crystals is pos/neg (blue/yellow)

yellow

crystals with negative biref are blue/yellow when parallel with polarized light

blue

crystals with pos biref are blue/yellow when parallel with polarized light

corticosteroid

-intracellular crystals

-from injection

-pos and neg biref

-flat, variable shaped plates

pos and neg

corticosteroid crystal biref is pos/neg

staphylococcus, streptococcus, hemophilus, neisseria

common joint bacteria

dec

glucose is inc/dec in inflammatory/septic disorders

microbiology

testing on synovial fluid

-gram stain

-cultures

-sensitivity

-antibiotic resistance

-most common bact: streptococcus, staphylococcus, hemophilus, neisseria

lower

synovial fluid glucose level is higher/lower than serum glucose

inc

total protein is inc/dec in inflammatory and hemorrhagic disorders

uric acid

-concentration similar to plasma concentration

-inc in gout (MSU crystals)