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HelpTest Code CRITH DNA Double-Stranded (dsDNA) Antibodies by Crithidia luciliae IFA, IgG, Serum
Reporting Name
dsDNA Ab by Crithidia IFA, IgG, SSpecimen Type
SerumSpecimen Required
Supplies: Sarstedt Aliquot Tube, 5 mL (T914)
Collection Container/Tube:
Preferred: Serum gel
Acceptable: Red top
Submission Container/Tube: Plastic vial
Specimen Volume: 0.3 mL
Collection Instructions: Centrifuge and aliquot serum into a plastic vial.
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Serum | Refrigerated (preferred) | 21 days | |
| Frozen | 21 days |
Reference Values
Negative
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Test Classification
This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.CPT Code Information
86255
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| CRITH | dsDNA Ab by Crithidia IFA, IgG, S | 58466-4 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 62925 | dsDNA Ab by Crithidia IFA, IgG, S | In Process |
| 37268 | Crithidia Interpretation | 69048-7 |
Method Name
Indirect Immunofluorescence
Useful For
Confirmation testing for dsDNA IgG antibodies in patients with clinical features of systemic lupus erythematosus or at-risk for disease
This test should not be used independently for monitoring treatment response or establishing remission.
Clinical Information
Double-stranded DNA (dsDNA) antibodies are systemic lupus erythematosus (SLE)-specific antibodies and are part of the immunology domain of the 2019 European League Against Rheumatism (EULAR)/American College of Rheumatology (ACR) classification criteria for SLE (1) as well as a previous guidance on SLE diagnosis.(2) The Crithidia luciliae indirect immunofluorescence test (CLIFT) is widely used as a confirmatory test following a positive dsDNA IgG result obtained by a solid-phase immunoassay due to its structural or analytical specificity.(3-5)
The CLIFT (dsDNA) test is indicated in patients who are positive for anti-cellular antibody (also known as antinuclear antibody [ANA]) homogeneous pattern (6) using HEp-2 substrate by indirect immunofluorescence assay (IFA) following a positive result for dsDNA IgG using a solid-phase immunoassay (eg, enzyme-linked immunosorbent assay or multiplex bead assay).(3,4) A positive CLIFT result is usually associated with the presence of moderate-to-high affinity dsDNA IgG antibodies. The CLIFT result may be negative and the immunoassay positive for dsDNA IgG in SLE patients with inactive (remission) disease or in patients with early disease.(3,4,7) Discordant results between CLIFT and solid-phase immunoassays may also be due to differences in the structural specificities of DNA analytes as well as the absence reliable reagents to harmonize available clinical tests.(3,5,8)
A minority of SLE patients may test negative using HEp-2 by IFA for nuclear antibodies.(9) Testing antibodies associated with the HEp-2 IFA cytoplasmic pattern such as ribosomal P IgG autoantibodies may be useful if features of neuropsychiatric disease are present.(9) Alternatively, patients may be tested for Smith, ribonuclear protein (RNP), SSA-52 and SSA-60 antibodies.(6,9)
Interpretation
A positive result for double-stranded DNA (dsDNA) IgG antibodies in the appropriate clinical context is highly suggestive of systemic lupus erythematosus (SLE). The presence of dsDNA IgG antibodies detected using the Crithidia luciliae indirect immunofluorescence test is highly specific for SLE with moderate sensitivity.
A negative result does not exclude a diagnosis of SLE.
Cautions
IgG antibodies to double-stranded DNA (dsDNA) by Crithidia luciliae indirect immunofluorescence test (CLIFT) is reported qualitatively (positive or negative). For semiquantitative assessment of IgG antibodies to dsDNA, see results from ADNA1 / Double-stranded DNA (dsDNA) Antibodies, IgG, Serum.
A positive result dsDNA IgG by enzyme-linked immunosorbent assay (ELISA) with a CLIFT negative result may be suggestive of early disease, inactive disease, or a false positive result.
A positive result for IgG antibodies to dsDNA by Crithidia luciliae in the absence of anti-dsDNA IgG by ELISA is also likely. In the absence of a positive homogeneous pattern antinuclear antibodies detected by indirect immunofluorescence, this autoantibody profile may occur in patients with diseases other than systemic lupus erythematosus (SLE).
A negative result does not exclude a diagnosis of SLE.
Method Description
Autoantibodies in the test specimen bind to the kinetoplast of Crithidia luciliae, a flagellate parasite which is bound to the slide. The kinetoplast is a complex network of interlocking circular double-stranded DNA molecules and is the substrate of this test. Washing removes excess serum from the substrate. Fluorescein conjugated antiserum added to the substrate attaches to the bound autoantibody. After a second washing step to remove excess conjugate, the substrate is cover slipped and viewed for fluorescent patterns with a fluorescent microscope. Observation of specific fluorescent patterns on the substrate indicates the presence of autoantibodies in the test sample.(Package insert: Bio-Rad Kallestad Crithidia luciliae Substrate. Bio-Rad Laboratories; 06/2015)
Day(s) Performed
Monday through Friday
Report Available
2 to 4 daysSpecimen Minimum Volume
See Specimen Required