Rheumatology Labs

Question 1

Percentage of healthy individuals with ANA titre
>1:40
>1:80
>1:160
>1:320

Answer 1

Percentage of healthy individuals with ANA titre
>1:40 = 20-30%
>1:80 = 10-12%
>1:160 = 5%
>1:320 = 3%

Question 2

ANA pattern molecular targets and disease associations
- Homogenous

Answer 2

Anti-DNA (SLE)
Anti-Histone (various incl. drug induced lupus, SLE, JIA)
Anti-DNP (nucleosomes)

Question 3

ANA pattern molecular targets and disease associations
- Speckled

Answer 3

Anti-Sm (SLE)
Anti-RNP (MCTD)
Anti-Ro/-La (SjD)
Anti-Jo1/ Mi-2 (DM)
Anti-Scl-70 (Systemic sclerosis)

Question 4

ANA pattern molecular targets and disease associations
- Centromere

Answer 4

Anti-centromere (systemic sclerosis)

Question 5

ANA pattern molecular targets and disease associations
- Nucleolar

Answer 5

Anti-nucleolar (SLE, systemic sclerosis)

Question 6

Non-Rheumatologic causes of positive ANA

Answer 6

Autoimmune disease
- hashimotos, Graves, autoimmune hepatitis, primary biliary cirrhosis
Infectious disease
- EBV, HIV, HCV, parvovirus 19, subacute bacterial endocarditis, syphilis
Malignancies
- lymphoma, paraneoplastic syndromes
Miscellaneous diseases
- IBD, interstitial pulmonary fibrosis

Drugs
- Hydralazine, carbamazepine, methyldopa, SSZ, PTU, isoniazid, anti-TNF, checkpoint inhibitor

Advancing age
First degree relatives
Not clinically relevant

Question 7

Conditions associated with a positive Rheumatoid Factor

Answer 7

RA
Other rheumatic conditions (SjD, SLE, vasculitis)
Infections (IE, syphilis, HepB/C, TB, HIV)
Other (Cirrhosis, mixed cryoglobulinaemia, primary biliary cirrhosis)
Healthy people (5-25%)

Question 8

False positive rate of Rheumatoid factor by age
20-60
60-70
>70

Answer 8

20-60 - 2-4%
60-70 - 5%
>70 10-24%

Question 9

How much more likely are RA patients with positive CCP to have erosive joint disease?

Answer 9

10 times more likely

Question 10

Other causes of positive CCP (unusual)?

Answer 10

Other CTD
Psoriasis
Tuberculosis
Alpha-1-antitrypsin deficiency

Question 11

Factors that increase rouleaux formation (and increase ESR)

Answer 11

Increased fibrinogen levels
Increased IgG levels

Question 12

Causes of elevated ESR

Answer 12

Infections (bacterial > viral)
Rheumatic diseases
Malignancy

Question 13

Factors resulting in higher ESR

Answer 13

Increasing age
Female sex
Anaemia
Macrocytosis
Pregnancy
Renal disease
Obesity
Smoking
IVIg

Question 14

Factors resulting in lower ESR

Answer 14

Polycythemia
Microcytosis
Hyperviscosity
Hypogammaglobulinaemia
Macrophage activation syndrome