Test Code #

046

CPT Code(s) #

86038, 86039, 86255, 86225, 86235 x4

Test Name

Drug Induced Lupus Panel (includes ANA, dsDNA, Ro, La, Sm, histone)

If Profile, Includes Tests:

N/A

Disease Name:

Systemic Connective Tissue Disease

Type of Study:

Serum Studies

Methodology:

Indirect Immunofluorescence (HEp-2) and Fluoroenzyme immunoassay (FEIA)

Substrate:

N/A

Reference Range:

ANA (Titer)
• Negative <40

dsDNA (IU/mL)
• Negative <10
• Equivocal 10-15
• Positive >10

Ro (SS-A) (U/mL)
• Negative <7
• Equivocal 7-10
• Positive >10

La (SS-B) (U/mL)
• Negative <7
• Equivocal 7-10
• Positive >10

Sm (U/mL)
• Negative <7
• Equivocal 7-10
• Positive >10

Histone (Units)
• Negative <1.0
• Weak Positive 1.0-1.5
• Moderate Positive 1.6-2.5
• Strong Positive >2.5

Units:

Titer, Units/mL

Schedule:

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:

Drug-induced lupus (DIL) is an autoimmune phenomenon where drug exposure leads to the development of systemic lupus erythematosus (SLE) like clinical features. More than 100 drugs have been identified as the cause of drug-induced lupus, with the list expanding with the development of newer biologic agents each year. DIL tends to be less severe than SLE, with symptoms usually resolving after discontinuation of the offending agent. The more common drugs implicated include hydralazine, procainamide, isoniazid, chlorpromazine, quinidine, minocycline, methyldopa. Some recombinant biologic agents such as tumor necrosis factor (TNF) antagonists and interferon alpha (IFN-α) also cause ANA’s more frequently than clinical lupus. DIL has clinical characteristics in common with late-onset lupus. Upto 10% of SLE are drug induced, and an estimated 15,000-30,000 cases of DIL occur in the US every year. Generally, arthralgias, myalgias, fevers, and serositis are more common in DIL. In contrast, renal involvement, central nervous system disease, malar rash, photosensitivity, and oral ulcers occur less frequently in DIL. The ANA in DIL tends to have a homogeneous pattern, although a speckled pattern may also be seen. Anti-histone antibodies are found in 75% of patients with DIL. However, anti-histone antibodies are also found in patients with idiopathic lupus; therefore, it is not a specific test. These antibodies may persist after the offending drug has been stopped and the symptoms have resolved. The anti-histone antibodies in idiopathic lupus are primarily detected against the H1 and H2B subunits. In contrast, the anti-histone antibodies found in most patients with DIL are directed against the H2A and H2B subunits. In the case of hydralazine, the anti-histone antibodies are directed against H1 and the H3–H4 complex. Besides anti-histone antibodies, antibodies to SSA/Ro and SSB/La can be found in patients presenting with the subacute cutaneous form of DIL. Antibodies to dsDNA are found in approximately half of the patients with idiopathic lupus but in less than 5% of patients with DIL.

Selected References

Solhjoo M, Goyal A, Chauhan K. Drug-Induced Lupus Erythematosus. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan 24.

Bruce C. Richardson. Drug-Induced Lupus Erythematosus. Editor(s): Daniel J. Wallace, Bevra Hannahs Hahn. Dubois' Lupus Erythematosus and Related Syndromes (Ninth Edition), Elsevier. 2019, Pages 377-388. "

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