Test Code #


CPT Code(s) #


Test Name

SCl-70 (for Scleroderma)

If Profile, Includes Tests:


Disease Name:

LE, other Connective Tissue Diseases

Type of Study:

Serum Studies





Reference Range:

Negative <20 Units
Weak Positive 20-39 Units
Moderate Positive 40-80 Units
Strong Positive >80 Units




Assay performed once per week. Report availability is within one week from the time of specimen receipt.

Specimen Requirements:

Collect 5-10 ml of blood in a red top or serum separator tube. If possible, separate serum from clot and place into red capped tube provided with Beutner Laboratories collection kits. If separation facilities are not available, the blood can be sent in the tube used for collection.

Sample Stability:

Stable at ambient temperature during shipment. If sample is stored prior to shipment, it is stable refrigerated (2-8ºC) up to five days and frozen (-20ºC or lower) up to one year.

Clinical Relevance:

The presence of Scl-70 antibodies (also referred to as topoisomerase I, topo-I or ATA) is considered diagnostic for systemic sclerosis (SSc). Scl-70 antibodies alone are detected in about 20 percent of SSc patients and are associated with the diffuse form of the disease, which may include specific organ involvement and poor prognosis. Scl-70 antibodies have also been reported in a varying percentage of patients with systemic lupus erythematosus (SLE). Negative results do not necessarily rule out the presence of SSc. If clinical suspicion remains, consider further testing for centromere, RNA polymerase III and U3-RNP, PM/Scl, or Th/To antibodies.

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