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Labratory Investigations - Rheumatology - Coggle Diagram
Labratory Investigations - Rheumatology
Tests
Inflammatory Markers
ESR
CRP
Rheumatoid factor (RF)
Anti CCP antibodies
Antinuclear antibodies (ANA) or Connective tissue disorders (CTD scrren)
ANCA (anti neutrophil cytoplasmic Ab)- ANCA-vasculitis
Uric acid- in gout
HLA B27- spondyloarthritis
CK (creatin kinase)- inflammatory myopathies (myositis)
vitamin D - osteoporosis
ESR - Erythrocyte sedimentation rate measures
Indirect Measurement of acute pahse proteins (fibrinogen most common) and immunoglobulins
Acute Phase Proteins
Produced in liver
Under control of inflammatory cytokines such as
IL-6
Il-1
TNF-α
Fibrinogen
Interacts with RBC to make them sediment faster
RBC morphology effect serum fibrinogen and can effet ESR
Non-inflammatory causes of ESR elevation
Aging
Female
Obesity
Pregnancy
Anaemia
Diabetes
Kidney Failure
Infection
Malignancy
Hyprgammaglobulinemia
ESR Technique
Aspirating diluted EDTA-blood
Place tube in vertical position
Measure distance fallen by erythrocytes after one hour
Use
Asses degreee of inflammtion
Diagnostic criteria for polymylagia rheumatic and GCA
Monitor disease activity and repsonse to therapy in inflammatory arthritis
CRP - C-REactive Protein
Acute phase protein produced by liver, measured bia ELIAS or nephelometry
Elevation occurs within 4h of tissue insure and peaks within 24-72h
Falls rapildy in abscene of inflammatory stimulus
Not effectedby
Anaemia
Renal failure
Other conditions that effect ESR
Increased CRP
Obesity
Use
Monitoring disease activity
RF - Rheumatoid Factor
Autoantibod to the Fc region of human IgG
IgM commonest isotype >IgG > IgA
Detection
Latex agglutination (1:20)
Nephelometry
ELISA
Sensitivity 70%
Specificity 80%
Presence of RF related to higher levels of diease activity and more aggressive join disease
Increased risk of extra-articular manifestions
Causes of Positive RF
Rheumatoid diseases
Sjogren's syndrome
MCTD
Sceroderma
Sarcoidosis
Chronic hepatic and pulmonary disease
Neoplasm
Infection
Cyglobulinaemia
Anti CCP Antibodies - Anti Citrullinated Protein Antibodies
Antibodies against amino acids formed by the post translations modifacation of arginine
Detection
ELISA
Sensitivity 70%
RF and CCP can occur years before onset of the diease
Evidence for association of anati CCP with more rapid radiological joint damage
No correlation with extra articular features of RA
ANA - Anti Nuclear Antibodies
Antibodies against specific nuclear antigens
Measurement
Indirect Immunofluorescence
Detecting the tire of the ANA and the pattern of the nuclear fluorescnce
ELIS
Enzyme linked immunosorbent adday
Identificationof specific ANA, has leargley replace ANA patterns
Significance
If ANA detected, Specific antigen may or may not be know
Positive ANA scree
More specific tests against knows antigens to determine the specific antigen
