Lab Test For SLE

LABORATORY TESTS 

1. General Tests (DL, RFT, UL, GDA, kolesterol, CRP)

1. Urinalysis 
2. Leukocyte Count 
3. Hematocrit 
4. Platelet Count 
5. Creatinine/Blood Chemistry 
6. Plasma Proteins 
7. Erythrocyte Sedimentation Rate 
8. C-Reactive Protein 
9. Blood Glucose 
10. Cholesterol 

2. Immune Testing 

1. ANA 
2. Anti-Sm 
3. anti-dsDNA 
4. anti-Ro (SS-A) 
5. anti-La (SS-B) 
6. anti-Histone 
7. anti-RNP 
8. Lupus Anticoagulant 
9. Anti-Cardiolipan Antibody 
10. Beta-2 Glycoprotein I 
11. Complement 
12. Cryoglobulins 

 Yang dilihat :

 

Urinalysis -

• Protein and cells in  urine   (early warning of kidney disease )

 

Complete blood count (CBC) - 

• Lekopeni
• Anemia krn defisiensi besi, inflamasi aktif atau hemolitik eritrosit, 
• Thrombocytopenia (related to anti-platelet antibodies)

 

Creatinine/Blood Chemistry - 

• Kreatinin naik ( because the kidneys are one of the primary target tissues in SLE, close monitoring is of great importance). In addition, a number of anti-rheumatic medications can cause injury to the kidney that may be reversed when detected early. 

 

Plasma Proteins - 

• Hipoalbuminemia (active inflammation, malnutrition or kidney disease). 
• Elevated levels of gamma globulins (IgG, IgA, IgM) are a sign of immune activation. 

 

Erythrocyte sedimentation rate (ESR) - is a non-specific sign 

• ESR may be elevated with active disease or with concomitant infection.

 

C-Reactive Protein (CRP) - 

• Elevated CRP levels may be suggestive of active infection in SLE patients or may rarely correlate with disease flares. Recent studies have shown that an elevated level may also be a risk factor for cardiovascular disease. 

 

CARDIOVASCULAR RISK SCREENING

 

SLE are 50x more likely to develop cardiovascular disease including strokes and heart attacks

 

Regular screening for cardiovascular risk factors :

• Diabetes (Blood glucose)
• Hyperlipidemia (especially LDL (fasting) are routinely monitored )
• Homocysteine

 

AUTOANTIBODIES

 

Under normal conditions antibodies are proteins that are made by your immune system to fight infection. 

In SLE these antibodies are misdirected against normal cellular components, forming immune complexes, which are potentially damaging to various tissues in the body in which they may deposit. 

 

Antinuclear Autoantibody (ANA) - is an antibody directed against material in the nucleus of cells and is the initial screening test for lupus. 

The ANA test is reported as a titer and a pattern. 

• The titer represents the number of times the blood needs to be diluted to eliminate the autoantibody from serum. A higher titer, therefore, represents a higher level of autoantibody in the serum although this is not a reliable measurement of disease activity. 
• The pattern of ANA seen on immunofluorescence may be associated with different autoimmune diseases. Any pattern can be seen in SLE but the peripheral (or rim) pattern is the most specific. 
• While 95% of lupus patients have a positive ANA, a small subset of lupus patients are ANA negative. In addition, 5% of the general population have a positive ANA and (never develop any clinical evidence of) lupus and the chances of this increases with age. 

A positive ANA test can be seen in a number of conditions : 

1. Autoimmune disease
2. Chronic infections
3. Post acute viral infections
4. Induced by certain medications. 

A positive ANA must, therefore, be interpreted within the context of a patient's symptoms and is not sufficient alone to make a diagnosis of lupus. More specific testing for the individual types of antoantibodies including anti-dsDNA, anti-Sm, anti-RNP, anti-Ro, anti-La are important in defining the underlying disease. 

 

Double-stranded DNA autoantibodies (dsDNA) - 

• Are antibodies directed against genetic material in the cell. 
• They are found in the majority of patients with lupus and elevated levels are characteristic of lupus affecting the kidneys. 
• These autoantibodies are highly specific for lupus and are only rarely associated with other autoimmune diseases or infections. These autoantibodies have been found to fluctuate with disease activity and are a useful tool for monitoring disease flares and remissions. 

 

Sm (Smith) Autoantibodies - 

• Are antibodies against nuclear material in the cell. 
• They are highly specific for SLE and are not described in other diseases. Unlike anti-dsDNA autoantibodies, anti-Sm autoantibodies are not useful for monitoring disease activity. 

 

Histone Autoantibodies - are antibodies directed against nuclear material in the cell. While they are present in many patients with lupus, the presence of this antibody is characteristic of drug-induced lupus. 

 

Antiphopholipid Antibodies - are antibodies directed against blood proteins, which bind to the surface of blood vessel walls and platelets. These autoantibodies include lupus anticoagulants (LA), anti-cardiolipan antibodies, anti- B2-glycoprotein I, antibodies responsible for a false positive VDRL (syphilis) test and anti-prothrombin antibodies. This group of autoantibodies is associated with an elevated risk of blood clotting, multiple spontaneous miscarriages and low platelet counts. While most patients remain asymptomatic, a small percentage of patients develop one of these illnesses and are said to have antiphopholipid (apL) syndrome which sometimes requires life-long anticoagulation to prevent future blood clotting. These autoantibodies can be associated with autoimmune disease (mostly SLE), chronic infections or may be related to medication use. 

 

Complement (C3, C4, CH50) - a group of enzymatic proteins (C1-C9) found in normal blood serum that participate and are consumed in the inflammatory process. Decreased levels of one or all three proteins can be seen in SLE and may signify kidney disease. In addition, low levels of complement with or without elevated levels of dsDNA may herald a disease flare. While findings are variable, serial monitoring of complement proteins may be used to predict a disease exacerbation. An inherited deficiency in one of these proteins may also predispose to developing SLE. 

 

Cryoglobulins - are immune complexes that form in SLE patients as a result of autoantibodies interacting with abnormal cellular components. These immune complexes may then deposit in tissues causing inflammation and damage. Detection of serum cryoglobulins serves as a crude indication of immune complexes circulating in the blood of SLE patients and may be related to the activity of the disease. 

 

CONCLUSION

Systemic Lupus is a chronic autoimmune disease with an unpredictable course. Because lupus is a potentially life-threatening disease, regular laboratory evaluation is essen tial in illustrating the variable manifestations of this disease. Early recognition of complications with careful clinical and laboratory assessment minimizes flares, side effects of medications and can allow patients to live healthy and productive lives.