| • | = very good screening test for most of the previously discussed antibodies |
| • | sensitive for SLE (95%) but not specific |
| • | titer does not reflect disease activity |
| • | a patient with a negative ANA is highly unlikely to have SLE and also unlikely to have any of the other CTD’s (CREST, MCTD, PSS, +/-SCLE) (except DLE) |
| • | SLE and MCTD ~100% ANA (+) |
| • | Dermatomyositis ~95% ANA (+) |
| • | Systemic Scleroderma/CREST ~95% |
evaluate three parameters:
1 - substrate (2 types):
| • | animal (less common today) – less sensitive; a negative test may in fact be positive if tested on human substrate |
| • | human Hep-s cells – more sensitive |
2 - titer:
| • | 1:80 or less is of no diagnostic value |
| • | a reasonable cut off point is 1:160 to 1:320 |
Positive fluorescent ANA in healthy persons (on Hep-2 cells):
titer: prevalence:
1:40 32%
1:80 13%
1:160 5%
1:320 3%
|
3 - pattern:
ANA:
|
Predominant antigen:
|
Disease:
|
|
|
|
Peripheral
|
nDNA
|
SLE
|
Homogenous
|
nDNA, histones
|
SLE, drug-LE
|
Nucleolar
|
Nucleolar RNA
|
SLE, SSc
|
Centromere
|
Kinetochore
|
CREST
|
Speckled
|
various RNP’s
|
MCTD, SLE, SSc, Sjogren’s
|
|