Flashcards in Diagnosis of Autoimmune Diseases Deck (15)
The proportion of people who tested positive, out of everyone with the disease
The proportion of people who tested negative, out of everyone without the disease
Positive predictive value
The proportion of people with the disease, out of everyone who tested positive
Negative predictive value
The proportion of people without the disease, out of everyone who tested negative
Non specific markers of systemic inflammation
CRP-produced acutely by liver in inflammation
ESR- viscocity of plasma increases in inflammatory response
Albumin decreases- liver is too busy
Complement decreases- complement factors consumed
Antinuclear antibodies (ANA)
Attack nuclei of lymphocytes in patients with SLE. Sometimes found in patients with infection.
2 specific types of ANA
Extractable nuclear antigens (ENA), or dsDNA
Describe the sensitivity and specificity of the ANA test
High sensitivity, low specificiy- identifies everyone with SLE, but some identified in infection
A test used to measure up to 20 autoimmune markers in a single serum sample
Multiplex assessment of non-organ specific autoantibody with a novel microbead-based immunoassay
Presents in RA. An autoantibody that targets the Fc region of IgG, but if too high, can precipitate, causing localised vasculitis or RA. Can also be seen in chronic infections.
Anti CCP (ACPA)
more specific biomarker for RAB. Present in 95% patients with RA. Autoantibody against proteins released in cell death.
The 2 types of Anti neutrophilic cytoplasmic antibodies (ANCA)
Cytoplasmic ANCA- target PR3 protein in cytoplasm
Perinuclear ANCA- target MPO protein in nucleus
What propotion of people with systemic vasculitis are ANCA negative?
10-50%. It often still presents after the disease has subsided.
Autoimmune biomarker for autoimmune liver disease
Anti-mitochondrial Abs for biliary sclerosis
Anti-smooth muscle and anti-liver/kidney/microsomal Abs found in autoimmune hepatitis