Also known as systemic sclerosis, it is a chronic connective tissue (tissue that supports, protects, and gives structure to other tissues) disease. The word “sclero” means hard while “derma” means skin i.e. hardening of the skin is the most visible manifestation (symptom) in this disease. It is classified as one of the autoimmune rheumatic diseases (diseases in which connective tissues are frequently targeted).
What is Anti SCL-70 lab test?
SCL-70 (also called topoisomerase 1 which is responsible for the relaxation of coiled DNA) is a 100-kD nuclear & nucleolar enzyme. The antibodies specific to SCL-70 are released during scleroderma condition & is found in about 60% patients with this connective tissue disease. This lab test is therefore used in detecting the presence of SCL-70 antibodies in blood which can help diagnose the connective tissue disease.
Why is Anti SCL-70 lab test done?
It is done:
To evaluate & diagnose patients with signs & symptoms of scleroderma
To evaluate other connective tissue diseases
In those whom antinuclear antibody test (blood test that looks for certain kinds of antibodies in body) comes positive
SCL-70 antibody test not useful in patients without demonstrable antinuclear antibodies
Firstly, the blood will be drawn from the vein
Blood sample is then collected in a test tube & sent to laboratory
The technician isolates serum from the blood sample and performs Anti SCL-70 lab test to detect SCL-70 antibodies & looks for possibility of a systemic scleroderma disease.
Do a positive SCL 70 result always denote scleroderma?
Yes, its positive test results show presence of SCL-70 antibodies which is consistent with diagnosis of scleroderma disease
Which tests help confirm scleroderma?
For confirmation, a pulmonary function test or breathing tests can be helpful in measuring how well the lungs are working. CT chest scan & ECG can also be helpful in determining extent of scleroderma.
Does ANA come positive when you have scleroderma?
Yes, in about 60% to 95% of scleroderma cases, Antinuclear antibody (ANA) test is positive.
What are the early signs seen in scleroderma?
The very first symptoms seen is Raynaud’s disease which is basically when small blood vessels in fingers & toes contract in response to cold temperatures or emotional distress. This causes fingers or toes to turn blue or feel painful/numb.
Are eyes affect during scleroderma?
The disease causes eyes to become very dry & sore. The vision is also affected & becomes blurred.
INTERPRETATION OF THE RESULTS:
“Positive”: Range is ‘> or = 1.0 U’ ; the positive result is consistent with a scleroderma diagnosis
“Negative”: Range is ‘< 1.0 U’ ; scleroderma disease not present.
This test is performed as Anti SCL-70 antibodies when found in blood can detect/diagnose conditions like systemic scleroderma, CREST syndrome (limited form of systemic scleroderma), & more severe scleroderma disease.