9 Diagnosis of autoimmune diseases Flashcards Preview

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Flashcards in 9 Diagnosis of autoimmune diseases Deck (17):
1

Define sensitivity

How good the test is in identifying people with the disease.

2

Define specificity

How good the test is at correctly defining people without the disease.

3

Define positive predictive value.

The proportion of people with a positive test result who have the disease.

4

Define negative predictive value.

The proportion of people with a negative test who do not have the disease.

5

7 non-specific markers of systemic inflammation.

ESP (plasma viscosity increases in infection).
CRP (liver produced, rises rapidly).
Ferritin.
Fibrinogen.
Haptoglobin.
Albumin.
Complement.

6

What are ANAs? How are they tested for?

Anti-nuclear antibodies
Slide with antigens. Sample introduced. Second wave of fluorescently labelled antibodies matching ANA introduced.

7

If an ANA test is positive, which two tests come next?

Anti-ds DNA (crithidia luciliae assay, farr assay, ELISA).
ENA's (immunoblats).

8

Which two antibodies are commonly found in rheumatoid arthritis? Which is more specific?

Rheumatoid factor.
Anti-CCP (ACPA). More specific. More severe disease - useful for prognosis.

9

What is the main target antigens of cytoplasmic ANCA?

PR3 (90%).

10

What is the main target antigen of perinuclear ANCA?

MPO (70%).

11

Which three conditions are ANCA found in?

ANCA associated systemic vasculinities (AASV):

Wegner's granulomatosis.
Microscopic polyangitis.
Churg-Staruss syndrome.

12

What use is ANCA in ANCA associated systematic vasculitides? (3).

Suggestive of diagnosis.
Return during -ve period may suggest flare.
Presence without clinical signs doesn't signal treatment need.

13

What antibodies are found in primary biliary sclerosis?

Anti-mitochondrial Ab.

14

Which antibodies are found in autoimmune hepatitis?

Anti-smooth muscle and anti-liver/kidney/microsomal.

15

What course do autoantibodies take in Type 1 Diabetes Mellitus?

Initially increase with destruction of pancreas but disappear with progression and total destruction of beta islet cells.

16

Which four autoantibodies are found in type 1 DM?

islet cell antibodies
anti-GAD65 , anti-GAD67
anti-insulinoma antigen (IA-2)
insulin autoantibodies (IAAs)

17

What is the role of autoantibodies in diagnosis of Type 1 DM?

Disease confirmation. -ve predicave value of 99%. Help identify relatives. Increased risk with greater variety of autoantibodies at younger age.

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