MLS Review - AUBF - Synovial Fluid

SYNOVIAL FLUID – COLOR MEDICAL LABORATORY SCIENCE REVIEW ANALYSIS OF URINE AND OTHER BODY FLUIDS: SYNOVIAL FLUID OUTLINE • Synovial Fluid o Functions of Synovial Fluid o Specimen Collection o Color o Clarity o Viscosity o Cell Count o Differential Count o Crystal Identification o Positive Vs Negative Birefringence o Chemical Examination o Microbiology Test o Serologic Tests: o Clinical Significance • • • • SYNOVIAL FLUID – RED • • SYNOVIAL FLUID • • • • • Aka as joint fluid From the word “Synovia” - egg white o Characteristic viscosity of synovial fluid is similar to the egg white Found in diarthrosis Ultrafiltrate of Plasma with hyaluronic acid o Synovium - joint cavity ▪ Composed of synoviocyte (produces hyaluronic acid) o When blood is filtered Hyaluronic acid - contribute to viscosity of the synovial fluid Colorless to pale yellow - Normal Deep Yellow - Inflammation Greenish tinge - Bacterial infection (septic arthritis) Red – Traumatic Tap, Hemorrhagic arthritis o Traumatic tap - accidental puncture of peripheral vessel in the joint area o Hemorrhagic arthritis - hemorrhage within joint cavity without accidental puncture Specimen is placed in three tubes Traumatic Tap o Decreasing intensity of red coloration COLOR CLOT FORMATION • Dark Red Light Red Yellowish + - - Dark Red Dark Red Dark Red - - - Hemorrhagic Arthritis COLOR CLOT FORMATION SYNOVIAL FLUID – CLARITY • • • • • FUNCTIONS OF SYNOVIAL FLUID • • • • Lubricates joints Reduce friction between bones Provides nutrients to the articular cartilage Lessen shock of joint compression occurring during activities (e.g. walking, jogging) • SYNOVIAL FLUID – VISCOSITY • SPECIMEN COLLECTION • • • Method of Collection: arthrocentesis o Synovial fluid should not clot when collected o When synovial fluid clotted, there is a presence of fibrinogen due to damage/diseased joint Volume: o Normal: <3.5 mL o Inflammation: >25 mL Distributed in the following tubes: o Na Heparin (sterile)/SPS: Microbiology o Liquid EDTA/Na Heparin: Hematology ▪ Powdered EDTA may be mistaken as crystals o Non-anticoagulated: Chemistry, other tests (sero) o Na Fluoride: Glucose analysis ▪ NaFl - anti-glycolytic Clear - Normal Turbid - Leukocytes, Fibrin, Cell Debris Opaque, Oily, Shimmering - Radiographic Contrast Media Milky - Crystal Ground Pepper-Like Inclusions - Ochronosis o Ochronotic shard - Ground pepper-like inclusions o Ochronosis - degenerative bone disease Free-Floating Rice Bodies –RA, degenerative synovium with fibrin • Normal o Able to form string - 4-6mm long o Normal Hyaluronic Acid Level: 0.3 - 0.4 g/dL Test o Ropes/Mucin Clot Test aka Hyaluronic polymerization test ▪ Reagent: 2-5% acetic acid (HAc) • Polymerize Hyaluronic acid forming clot o Reporting: ▪ Good - Solid clot ▪ Fair - Soft Clot ▪ Low - Friable clot ▪ Poor - No clot 1 SYNOVIAL FLUID – CELL COUNT • • • • Hemocytometry is used to count cells Diluting Fluids: o NSS with Methylene Blue o Hypotonic Saline (0.3%) - for WBC count; cause RBC lysis o Saline with Saponin - for WBC count; cause RBC lysis Do not use acetic acid for cell count o HAc will polymerize hyaluronic acid causing clot For very viscous fluid o Add a pinch hylauronidase to 0.5 mL synovial fluid OR o Add 1 drop of 0.05% hyaluronidase in phosphate buffer per mL of fluid ▪ Incubate at 37C for 5 minutes SYNOVIAL FLUID – DIFFERENTIAL COUNT • Normal Values o RBC: <2000/uL o WBC: <200/uL o WBC Differential ▪ Monocytes/Macrophages: 65% ▪ Neutrophils: <25% ▪ Lymphocytes: <15% CELLS AND INCLUSIONS SEEN IN SYNOVIAL FLUID CELLS DESCRIPTION CRYSTAL IDENTIFICATION CRYSTAL SHAPE Monosodium Urate (MSU) Needles Calcium Rhombic Pyrophosphate square, rods dihydrate (CPPD) Cholesterol Notched, Rhombic plates Positive birefringence Corticosteroid Flat, variableshaped plates Injections Calcium oxalate Envelopeshaped Positive & Negative birefringence Negative birefringence Hydroxyapatite/ Apatite (Calcium phosphate) Small particles Requires electron microscopy No birefringence Osteoarthritis, calcified cartilage degeneration • • Neutrophils Macrophages (Monocytes) (most common WBC in synovial fluid) Synovial Lining Cells Large mononuclear leukocytes, may be vacuolated Similar to macrophage, but may be multinucleated, resembling a mesothelial cell LE Cells Neutrophil containing characteristic ingested “round body” Reiter Cells Vacuolated macrophage with ingested nutrophil RA Cells Neutrophil with dark (Ragocytes) cytoplasmic granules containing immune complexes Cartilage Cells Large, multinucleated cells Rice Bodies Macroscopically resemble polished rice Microscopically show collagen & fibrin Fat Droplets Refractile intracellular & extracellular globules. Stained w/ Sudan dyes Hemosiderin Inclusions within clusters of synovial cells Normal, but may indicate viral inection Negative birefringence Pseudogout (degenerative arthritis) Extracellular Renal dialysis POSITIVE VS NEGATIVE BIREFRINGENCE SIGNIFICANCE Polymorphonuclear Bacterial sepsis, crystalleukocytes (multiinduced inflammation lobular) Lymphocytes Mononuclear leukocytes Non-septic inflammation COMPENSATED POLARIZED SIGNIFICANCE LIGHT Negative Gout (↑ uric birefringence acid) • • • Normal Relationship between the velocity of light from the microscope and the arrangement of molecules of crystal All synovial fluid crystals have birefringence except of hydroxyapatite o Hydroxyapatite/ Apatite - invisible under polarizing microscope Polarizing Microscope - determines birefringence of crystal Positive Birefringence o Shows that the crystal has yellow color’ o If velocity of light is parallel to the arrangement of molecules of the crystals, it is positive Negative Birefringence o Shows that the crystal has blue color o If velocity of light is perpendicular to the arrangement of molecules of the crystals, it is negative Lupus Erythematosus Non-specific inflammation, Reiter syndrome Immunologic inflammation, rheumatoid arthritis Osteoarthritis • SYNOVIAL FLUID – CHEMICAL EXAMINATION • Tuberculosis, septic and rheumatoid arthritis Traumatic injury Chronic inflammation Pigment vilonodular sinovitis Positive Birefringence Negative Birefringence Compensated Polarizing Light - used to identify type of birefringence o Uses red compensator • • Glucose o Most frequently tested chemistry test o Blood Glucose – SF Glucose = <10 mg/dL (Normal) o Example: ▪ 99 mg/dL (FBS) – 90 mg/dL (SFG) = 9 mg/dL ▪ 99 mg/dL (FBS) – 40 mg/dL (SFG) = 59 mg/dL o Decreased: infection Lactate o Normal: <250 mg/dL o Increased: infection Protein o Normal: 3 g/dL o Increased: inflammatory & hemorrhagic disorders 2 • Uric Acid o Normal: same as blood uric acid o Increased: Gout MICROBIOLOGY TEST • Common organisms that infect Synovial Fluid: o Staphylococcus aureus - most redominant o Streptococcus o Haemophilus o N. gonorrheae - gonococcal arthritis SEROLOGIC TESTS: • • Autoantibody detection (SLE, RA) o Antinuclear antibody (ANA), Rheumatoid factor (Rf) Serologic tests for Lyme Disease o Lyme disease - frequent complication is arthritis ▪ Caused by bacteria Borrelia burgdorferi CLINICAL SIGNIFICANCE • • • • • I - Non-inflammatory o Significance: Degenerative joint disorder (osteoarthritis) o Color & Clarity: Clear, Yellow fluid o Viscosity: Good o WBC Count: <1,000/uL o Neutrophils: <30% o Glucose: Normal o Others: NA IIa - Inflammatory (Immunologic) o Significance: Immunologic disorders (RA, SLE, etc) o Color & Clarity: Cloudy, yellow fluid o Viscosity: Poor o WBC Count: 2,000 – 75,000/uL o Neutrophils: >50% o Glucose: Decreased o Others: Autoantibody testing IIb - Inflammatory (Crystal-induced) o Significance: Gout (MSU), Pseudogout o Color & Clarity: Cloudy or milky fluid o Viscosity: Low o WBC Count: Up to 100,000/uL o Neutrophils: <70% o Glucose: Decreased o Others: (+) crystals III - Septic o Significance: Microbial Source o Color & Clarity: Cloudy, green fluid o Viscosity: Variable o WBC Count: 50,000 – 100,000/uL o Neutrophils: >75% o Glucose: decreased ▪ Lactate is increased o Others: (+) gram stain & culture IV - Hemorrhagic o Significance: Traumatic injury Coagulation deficiencies o Color & Clarity: Cloudy, red fluid o Viscosity: Low o WBC Count: Equal to Blood o Neutrophils: Equal to Blood o Glucose: Normal o Others: (+) RBC 3