Double stranded DNA antibodies (RIA Assay)

Diagnostic Use

The presence of high affinity circulating antibodies directed against double stranded DNA (dsDNA) is largely confined to SLE. These antibodies may be involved in the pathogenesis of SLE when deposited as immune complexes in organs and tissues. Measurement of dsDNA antibodies has prognostic value; most SLE patients in remission, but with high antibody levels, later experience flare ups of the disease. Additionally, rapid increases in antibody level are often associated with major disease symptoms. Serial measurement of antibody level may therefore enable improved patient management when correlated with associated clinical and other laboratory findings.

Department

Immunology

Delphic Registration Code

DDNA

Synonyms

DNA antibodies
dsDNA
Farr Assay

Turnaround Time

14 days

Test Code

6855

Specimen Type

• Serum

Specimen Requirements

Tube/Container Type:

Preferred

• Serum (Red Cap)

Preferred if West Coast

• SST II (Gold Cap)

Acceptable

• SST II (Gold Cap)

Preferred Sample Volume (ml)

5

No of Samples Required

1

Paediatric Specimen Requirements

Tube/Container Type:

Preferred

• SST II (Gold Cap)

Acceptable

• SST II (Gold Cap)

Preferred Sample Volume (ml)

0.5

Interferences

Grossly haemolytic, icteric (jaundiced), or lipaemic specimens.
Do not use samples from patients undergoing radiotherapy with gamma emitting isotopes.

Interferences:
The following blood components do not have a significant effect (± 20% of expected) on the test results up to the stated concentrations below.
Haemoglobin 1.03 mmol/L (4.0 mg/mL)
Bilirubin 85.5 µmol/L (0.5 mg/mL)
Triglyceride 3.4 mmol/L (30 mg/mL)

Additional Specimen Information

Manufacturer's instructions state only serum may be used for this assay.

Aliquot Instructions

Sample Type

• Serum

Minimum Volume (ml)

0.1

Transport to Lab

Ambient (8 - 24 degrees Celsius)
Chilled (2 - 8 degrees Celsius)

Additional Referral/Aliquot Information

100 uL serum - minimum, 1 mL serum - preferred.
Serum can be stored for up to three weeks at 2C – 8C, or up to 6 months at -20C

Interpretation

Whilst dsDNA antibodies are associated with SLE they are not diagnostic in isolation. Presence and titre of anti‑dsDNA should be interpreted in conjunction with other laboratory (e.g. anti-Sm, raised CRP) and clinical information to aid in diagnosis.

Reference Intervals

Normal Range is 0‑7 IU/mL.

 

Test Method

RIA (radioimmunoassay)

Non-Funded Test Cost

$34.70 (Exclusive of GST)

Billing Code

6855

Contact Information

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