Connective Tissue Disease Screen

Alternative Names/Synonyms	ANA Screen, CTD Screen
Laboratory	Core Laboratory & Transfusion Medicine
Sub-section	Biochemistry
Specimen Type	Blood
Test Code	CTDAB

Supporting Documents

Connective Tissue Disease Reflex Algorithm

Clinical Significance (If applicable)

Detecting anti-nuclear autoantibodies (ANA) and assisting in the diagnosis of systemic lupus erythematosus, Sjögren's Syndrome, scleroderma, idiopathic inflammatory myopathy and mixed connective tissue disease.

The screen includes dsDNA, centromere B, centromere A, Sm (smith), RNP, Ro60, Ro52, Scl70, La (SS-B), Jo1, ribosomal P, RNA polymerase III, PM/Scl, MI-2, PCNA, Th/To, Ku. A negative result suggests the patient is negative for the 17 autoantibodies included in the screen. This screen has replaced previous ANA testing by immunofluorescence.

Specimen Requirements (Sample Type)

Serum

Specimen Requirements (Volume (mL))

0.5 mL

Specimen Requirements (Tube Type)

Serum (Gold SST)
Collection Containers – Tube Types

Collection Requirements

Collection Instructions

Storage / Shipment Details

Freeze for shipment or if assay not completed within 2 days.

Sample Stability

Room Temperature: 8 Hours

Fridge: 48 hours @ 2-8°C

Freezer: 1 year @ -20°C

Cause for Rejection

Specimen Acceptability and Transport Guidance

Instrument, Methodology

BIO-FLASH, immunoassay

Test Availability

Weekdays

Routine Turnaround Time

1 week

Reference Ranges

< 20 CU

In case of discrepancies, always interpret results using reference ranges as stated on laboratory reports and/or electronic patient chart.

Laboratory Contact Information

416-586-4800 extension 4688

Ordering Practices

The following reflex algorithm is implemented. The ENA7 Screen is an additional screen used to determine whether or not reflex testing for individual auto-antibodies should be performed.

Orders can be placed for the CTD Screen OR individual auto-antibodies (DsDNA, Centromere B, Sm, RNP, Ro60, Ro52, Scl70, SSB, Jo1) but they cannot be ordered together. If an individual auto-antibody (ie. dsDNA) is ordered alongside the CTD Screen, the individual auto-antibody ordered will be cancelled to prevent duplicate testing.

If the CTD screen is positive and all subsequent reflexed tests are negative, the following auto-antibodies may have be positive: Ribosomal P, RNA Polymerase III, PM/Scl, MI-2, PCNA, Th/To, Ku and/or Centromere A.