Myositis Profile-IgG(16 Antigen)

Blood

1 parameters

Report in 144Hrs

At Home

No Fasting Required

Details

Autoimmune myopathy antibody panel.

₹22,999₹34,631

34% OFF

Parameters

List of Tests
- Myositis Profile-IgG(16 Antigen)

Myositis Profile-IgG(16 Antigen) - Comprehensive Medical Guide

Why is it done?
- Detects IgG autoantibodies against 16 different myositis-associated antigens to diagnose inflammatory muscle diseases and autoimmune myositis conditions
- Primary indication for patients presenting with muscle weakness, myalgia, elevated creatine kinase (CK) levels, and clinical suspicion of inflammatory myopathy
- Assists in diagnosing polymyositis, dermatomyositis, inclusion body myositis, overlap syndromes, and other forms of autoimmune myositis
- Identifies specific autoimmune targets including myositis-specific antibodies (MSA) and myositis-associated antibodies (MAA) for precise classification of disease subtype
- Used for disease prognosis, treatment planning, monitoring disease progression, and assessing response to immunosuppressive therapy
- Recommended when conventional serological testing (ANA, complement levels) yields inconclusive results and myositis remains clinically suspected
- The 16-antigen panel comprehensively evaluates multiple myositis-associated antigens including Jo-1, PL-7, PL-12, EJ, OJ, Mi-2, U1-RNP, PM-Scl-75, PM-Scl-100, Ku, KJ, P155, P140, TIF1-gamma, and nucleolar antigens
Normal Range
- Negative Result: < 1.0 index (or < 0.9 U/mL depending on laboratory methodology) - indicates absence of measurable IgG autoantibodies to myositis-associated antigens
- Equivocal/Borderline Range: 1.0-1.5 index - may represent early disease, weak antibody response, or false-positive; clinical correlation and repeat testing recommended
- Positive Result: > 1.5 index (or > 1.5 U/mL) - indicates significant presence of IgG autoantibodies and supports diagnosis of inflammatory myopathy
- Reference units: Index value or U/mL (Units per milliliter), with cutoff thresholds determined by individual laboratory reference standards and assay methodology
- Normal/Negative interpretation: Autoimmune myositis less likely; consider alternative diagnoses such as infectious myositis, toxic myopathy, metabolic myopathy, or muscular dystrophy
- Abnormal/Positive interpretation: Presence of myositis-specific or myositis-associated antibodies; strongly suggestive of autoimmune inflammatory myopathy requiring further diagnostic confirmation and clinical correlation
- Laboratory reporting typically identifies specific positive antibodies and their individual titers within the 16-antigen panel for precise characterization of autoimmune profile
Interpretation
- Positive Anti-Jo-1 antibody: Indicates antisynthetase syndrome with polymyositis, interstitial lung disease, arthritis, Raynaud's phenomenon, and mechanic's hands; represents approximately 20-30% of myositis cases
- Positive Anti-Mi-2 antibody: Associated with dermatomyositis with favorable prognosis, rapid response to corticosteroids, and lower risk of interstitial lung disease and malignancy
- Positive Anti-TIF1-gamma (p155) antibody: Strongly associated with dermatomyositis and increased risk of malignancy; warrants comprehensive cancer screening in adult-onset cases
- Positive Anti-PL-7, Anti-PL-12, Anti-EJ, Anti-OJ antibodies: Other antisynthetase antibodies indicating antisynthetase syndrome with myositis and interstitial lung disease; associated with worse prognosis than anti-Jo-1 alone
- Positive Anti-PM-Scl antibodies (75 and 100 kDa): Associated with overlap myositis-scleroderma, polymyositis features, and systemic sclerosis overlap syndromes
- Positive Anti-Ku antibody: Indicates overlap syndrome with myositis and systemic lupus erythematosus (SLE); associated with severe disease manifestations
- Positive Anti-U1-RNP antibody: Suggests overlap syndrome with mixed connective tissue disease (MCTD) and myositis; associated with Raynaud's phenomenon and arthritis
- Negative results with clinical myositis: 'Seronegative myositis' occurs in approximately 20-40% of myositis cases; diagnosis relies on clinical features, electromyography (EMG), muscle imaging (MRI), and muscle biopsy findings
- Multiple positive antibodies: May indicate specific overlap syndromes or simultaneously present autoimmune conditions; clinical presentation guides interpretation
- Antibody persistence: Positive results may persist for years even with clinical remission; antibody presence does not necessarily indicate active disease requiring treatment adjustment
- Factors affecting interpretation: Recent immunosuppressive therapy, immunomodulatory treatment, disease duration, and prior antibody serology results should be considered in result interpretation
- False positives possible in: Systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), Sjögren's syndrome, scleroderma, and other autoimmune conditions with cross-reactive antibodies
Associated Organs
- Skeletal Muscle: Primary target organ with inflammatory infiltration, necrotizing changes, and autoimmune destruction leading to proximal muscle weakness and functional impairment
- Lungs and Respiratory System: Frequently involved in antisynthetase syndrome with interstitial lung disease (ILD), pulmonary fibrosis, and dyspnea; risk increases with certain antibodies (anti-Jo-1, anti-PL-7, anti-PL-12)
- Skin: Involved in dermatomyositis with characteristic heliotrope rash, Gottron's papules, photosensitive dermatitis, and increased malignancy risk in anti-TIF1-gamma positive patients
- Heart: Cardiopulmonary involvement manifesting as myocarditis, arrhythmias, congestive heart failure, and coronary artery disease; more common in myositis-scleroderma overlap syndrome
- Esophagus and GI Tract: Involved in myositis with pharyngeal/esophageal dysphagia, reflux, aspiration risk, and gastrointestinal dysmotility; particularly common in antisynthetase syndrome
- Connective Tissue System: Involvement in overlap syndromes affecting joints (arthritis), tendons, ligaments, and fasciae; particularly in myositis-scleroderma and myositis-SLE overlap
- Nervous System: Involvement in inclusion body myositis and certain overlap syndromes; demyelinating disease and autonomic dysfunction reported in specific antibody-positive subsets
- Malignancy: Significantly increased cancer risk with certain antibodies, particularly anti-TIF1-gamma (dermatomyositis), anti-NXP2/MJ, and anti-CADM-140; screening warranted in specific populations
- Immune System: Global autoimmune dysregulation with formation of pathogenic autoantibodies, complement activation, T-cell infiltration, and immunologic memory indicating persistent autoimmune state
Follow-up Tests
- Creatine Kinase (CK) total and isoenzymes: Assess muscle damage severity and monitor treatment response; expected to decrease with immunosuppressive therapy in active myositis
- Aldolase, Lactate Dehydrogenase (LDH), Aspartate Aminotransferase (AST), Alanine Aminotransferase (ALT): Auxiliary muscle damage markers providing comprehensive assessment of muscle and liver involvement
- Antinuclear Antibody (ANA) panel: Screen for concurrent autoimmune conditions; if positive, pursue extended autoimmune serologies including anti-Ro/SSA, anti-La/SSB, anti-Sm, anti-dsDNA
- Comprehensive Metabolic Panel (CMP): Monitor renal function, electrolytes, and hepatic function as baseline and during immunosuppressive therapy assessment
- High-Resolution CT (HRCT) Chest: Evaluate for interstitial lung disease (ILD), particularly in antisynthetase syndrome; assess baseline and monitor for progression during follow-up
- Pulmonary Function Tests (PFT): Determine extent of lung disease with forced vital capacity (FVC), diffusing capacity (DLCO), and flow-volume loops; baseline and annual monitoring recommended
- Electromyography (EMG) and Nerve Conduction Studies (NCS): Confirm myopathic pattern consistent with inflammatory myositis; help differentiate from neurogenic causes and inclusion body myositis
- Muscle Imaging (MRI with STIR sequences): Identify inflammation and edema in affected muscles, guide biopsy site selection, and assess disease distribution and severity
- Muscle Biopsy with Immunohistochemistry: Definitive diagnostic test showing inflammatory infiltrate pattern, fiber necrosis, and complement deposition; indicated for seronegative cases or diagnostic uncertainty
- Complement levels (C3, C4): Evaluate immune activation status; may be low in active disease and help monitor disease activity and immunosuppressive therapy effectiveness
- Erythrocyte Sedimentation Rate (ESR) and C-Reactive Protein (CRP): Inflammatory markers; assess disease activity and response to treatment, though CRP may be falsely negative in some myositis cases
- Malignancy Screening: Indicated based on antibody subtype; for anti-TIF1-gamma positive patients: comprehensive cancer screening with age-appropriate imaging, tumor markers, and clinical evaluation
- Repeat Myositis Antibody Panel: Consider at 3-6 month intervals to assess antibody persistence, titer changes with treatment, or development of additional antibodies indicating disease evolution
- Rheumatology Consultation: Strongly recommended for all positive results to establish diagnosis, guide immunosuppressive therapy selection, assess organ involvement, and coordinate multidisciplinary care
- Monitoring frequency: Every 3-6 months initially with abnormal results, then annually during remission; increased monitoring during treatment changes or clinical deterioration
Fasting Required?
- Fasting Required: No - This is a serum immunological test that does not require patient fasting prior to blood collection
- Sample type: Serum collected via venipuncture into standard serum separator tube (SST) or similar appropriate tube per laboratory protocol
- No dietary restrictions: Patients may eat and drink normally before the test; no specific food or liquid avoidance necessary
- Medication considerations: Most routine medications do not interfere with antibody testing; however, recent immunosuppressive therapy or immunomodulatory drugs may theoretically reduce antibody titers
- Timing note: Optimal testing should be performed before initiating corticosteroids or immunosuppressive therapy when autoantibody titers are typically highest for improved detection sensitivity
- Sample handling: Blood samples should be collected during normal business hours and processed promptly; serum should be separated and stored refrigerated or frozen per laboratory specifications
- Turnaround time: Typically 5-14 business days depending on laboratory; specialized immunological testing may require referral to reference laboratory with longer processing times
- No activity restrictions: Patients may resume normal activities immediately after blood draw; no post-test restrictions or precautions necessary

How our test process works!