Synovial fluid analysis

WHAT TO PUT ON LAB FORM

  • – appearance
  • – WCC
  • – RBC
  • – microscopy + culture
  • – protein
  • – LDH
  • – glucose
  • – crystals

INTERPRETATION

Appearance

  • normally clear to light yellow

WCC

  • Suggests:
    -> infection
    -> gout
    -> pseudogout
    -> inflammatory arthritides (RA, seronegative)

RCC

  • Suggests:
    -> traumatic tap
    -> haemarthrosis (spontaneous or traumatic)

Protein

  • > 30g/L = exudate
    -> infection and inflammatory arthritides

LDH

  • >300IU/L
    -> RA
    -> gout
    -> infection

Glucose

  • < ½ serum
    -> infection
    -> severe inflammation

Crystals

  • Either:
    -> gout: monosodium urate, needle shaped
    -> pseudogout: calcium pyrophosphate dehydrate, birefringent, rhomboidal crystals
  • Crystals:
    • Calcium pyrophosphate (pseudogout)
      • Positive birefringence
      • Rhomboid shaped, Yellow crystals
    • Calcium urate (Gout)
      • Negative birefringence
      • Needle shaped crystals, Blue crystals
  • Gram stain
    • Positive in <25% gonococcal infections
    • Positive in 50-75% non-gonococcal
Joint-Effusion-Analysis-Table-590x487
Joint-Fluid-analysis-2
CCC 700 6

Critical Care

Compendium

…more CCC

Chris is an Intensivist and ECMO specialist at The Alfred ICU, where he is Deputy Director (Education). He is a Clinical Adjunct Associate Professor at Monash University, the Lead for the  Clinician Educator Incubator programme, and a CICM First Part Examiner.

He is an internationally recognised Clinician Educator with a passion for helping clinicians learn and for improving the clinical performance of individuals and collectives. He was one of the founders of the FOAM movement (Free Open-Access Medical education) has been recognised for his contributions to education with awards from ANZICS, ANZAHPE, and ACEM.

His one great achievement is being the father of three amazing children.

On Bluesky, he is @precordialthump.bsky.social and on the site that Elon has screwed up, he is @precordialthump.

| INTENSIVE | RAGE | Resuscitology | SMACC

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