Test directory: Extended Myositis Panel

Note¹:

Interpretive Information:
 
29 AU/mL or less    .......... Negative
30 - 40 AU/mL       .......... Equivocal
41 AU/mL or Greater .......... Positive
 
SSA-52 (Ro52) and/or SSA-60 (Ro60) antibodies are
associated with a diagnosis of Sjogren syndrome,
systemic lupus erythematosus (SLE), and systemic
sclerosis. SSA-52 antibody overlaps significantly
with the major SSc-related antibodies. SSA-52
(Ro52) antibody occurs frequently in patients with
inflammatory myopathies, often in the presence of
interstitial lung disease.
.

Note²:

Interpretive Information:
 
29 AU/mL or less    .......... Negative
30 - 40 AU/mL       .......... Equivocal
41 AU/mL or Greater .......... Positive
.

Note³:

Interpretive Information:
 
19 Units or Less    .......... Negative
20 to 39 Units      .......... Weak Positive
40 to 80 Units      .......... Moderate Positive
81 Units or Greater .......... Strong Positive
 
Smith/RNP antibodies are frequently seen in
patients with mixed connective tissue disease
(MCTD) and are also associated with other systemic
autoimmune rheumatic diseases (SARDs) such as
systemic lupus erythematosus (SLE), systemic
sclerosis, and myositis. Antibodies targeting the
Smith/RNP antigenic complex also recognize Smith
antigens, therefore, the Smith antibody response
must be considered when interpreting these results.
.

Note⁴:

Interpretive Information:
 
29 AU/mL or less    .......... Negative
30 - 40 AU/mL       .......... Equivocal
41 AU/mL or Greater .......... Positive
 
Presence of Jo-1 (antihistidyl transfer RNA (tRNA)
synthetase) antibody is associated with
polymyositis and may also be seen in patients with
dermatomyositis. Jo-1 antibody is associated with
pulmonary involvement (interstitial lung disease),
Raynaud phenomenon, arthritis, and mechanic's
hands (implicated in antisynthetase syndrome).
.

Note⁵:

Interpretive Information:
The presence of PM/Scl-100 IgG antibody along with a positive ANA IFA nucleolar pattern is associated with connective tissue diseases such as polymyositis (PM), dermatomyositis (DM), systemic sclerosis (SSc), and polymyositis/systemic sclerosis overlap syndrome. The clinical relevance of PM/Scl-100 IgG antibody with a negative ANA IFA nucleolar pattern is unknown. PM/Scl-100 is the main target epitope of the PM/Scl complex, although antibodies to other targets not detected by this assay may occur

This test was developed and its performance characteristics determined by ARUP Laboratories
It has not been cleared or approved by the US Food and Drug Administration. This test was performed in a CLIA certified laboratory and is intended for clinical purposes
.

Note⁶:

Interpretive Information:
The presence of fibrillarin (U3-RNP) IgG antibodies in association with an ANA IFA nucleolar pattern is suggestive of systemic sclerosis (SSc). In SSc, these antibodies are associated with distinct clinical features, such as younger age at disease onset, frequent internal organ involvement (pulmonary hypertension, myositis and renal disease). Fibrillarin antibodies are detected more frequently in African American patients with SSc compared to other ethnic groups. Strong correlation with ANA IFA results is recommended

In a multi-ethnic cohort of SSc patients (n=98),
U3-RNP antibodies detected by immunoblot had an agreement of 98.9 percent with the gold standard immunoprecipitation (IP) assay. Approximately 71 percent (5/7) of the borderline U3-RNP results with ANA nucleolar pattern in this cohort were IP negative

This test was developed and its performance characteristics determined by ARUP Laboratories
It has not been cleared or approved by the US
Food and Drug Administration. This test was performed in a CLIA certified laboratory and is intended for clinical purposes
.

Note⁷:

Interpretive Information:
If present, myositis-specific antibodies (MSA) are specific for myositis, and may be useful in establishing diagnosis as well as prognosis. MSAs are generally regarded as mutually exclusive with rare exceptions; the occurrence of two or more MSAs should be carefully evaluated in the context of patient's clinical presentation. Myositis-associated antibodies (MAA) may be found in patients with CTD including overlap syndromes, and are generally not specific for myositis. The following table will help in identifying the association of any antibodies found as either MSAs or MAAs

Antibody Specificity .....................MSA ......MAA
SSA 52 (Ro)(ENA) Antibody IgG .......................X
SSA 60 (Ro)(ENA) Antibody IgG .......................X
Smith/RNP (ENA) Ab, IgG .............................X
Jo-1 (histidyl-tRNA synthetase) Ab, IgG ...X
PL-12 (alanyl-tRNA synthetase) Antibody ...X
PL-7 (threonyl-tRNA synthetase) Antibody ..X
EJ (glycyl-tRNA synthetase) Antibody ......X
OJ (isoleucyl-tRNA synthetase) Antibody ...X
SRP (Signal Recognition Particle) Ab ......X
Ku Antibody .........................................X
PM/SCL 100 Antibody, IgG ............................X
Fibrillarin (U3 RNP) Ab, IgG ........................X
Mi-2 (nuclear helicase protein) Antibody ..X
P155/140 Antibody .........................X
TIF-1 gamma (155 kDa) Ab ..................X
SAE1 (SUMO activating enzyme) Ab ..........X
MDA5 (CADM-140) Ab ........................X
NXP2 (Nuclear matrix protein-2) Ab ........X
This test was developed and its performance characteristics determined by ARUP Laboratories
It has not been cleared or approved by the US
Food and Drug Administration. This test was performed in a CLIA certified laboratory and is intended for clinical purposes

See report..