digene HC2 CT/GC DNA Test

The digene HC2 CT/GC DNA Test provides combined qualitative detection of Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (GC) DNA as an initial test to identify symptomatic or asymptomatic women with CT and/or GC infection. Follow-up testing with the digene HC2 CT-ID DNA Test and the digene HC2 GC-ID DNA Test is required to identify the organism(s) present in a specimen that tests postive with the digene HC2 CT/GC DNA Test (see table). For high-volume sample throughput testing, the digene HC2 CT/GC DNA Test may be performed using the Rapid Capture System (RCS) instrument.

Repeat testing ID test verification algorithm

Using the digene HC2 CT/GC DNA Test, specimens with RLU/CO ratios < 1.0 do not contain Chlamydia trachomatis or Neisseria gonorrhoeae DNA or contain DNA levels below the detection limit of the assay. If the initial digene HC2 CT/GC DNA Test result RLU/CO is ≥1.0, specimens are considered positive and follow-up testing with the digene HC2 GC-ID DNA Test and digene HC2 CT-ID DNA Test result is required. Specimens found positive by the digene HC2 CT/GC DNA Test that are determined to be negative after testing with both the digene HC2 CT-ID DNA Test and the digene HC2 GC-ID DNA Test should be reported as "No Chlamydia trachomatis or Neisseria gonorrhoeae DNA detected". + = RLU/CO ≥ 1.0; – = RLU/CO < 1.0; NA = not applicable. 

Initial HC2 CT/GC DNA Test	Repeat HC2 CT-ID DNA Test	Repeat HC2 GC-ID DNA Test	Final result interpretation
+	+	+	+ for CT and GC DNA
	+	–	+ for CT DNA; no GC DNA
	–	+	+ for GC DNA; no CT DNA
	–	–	– for CT and GC DNA
–	NA	NA	– for CT and GC DNA

The digene HC2 CT/GC DNA Test is a nucleic acid hybridization assay with signal amplification that utilizes microplate chemiluminescent detection. Specimens containing the target DNA hybridize with a specific CT/GC RNA probe cocktail. The resultant RNA–DNA hybrids are captured onto the surface of a microplate well that is coated with antibodies specific for RNA–DNA hybrids. Immobilized hybrids are then reacted with alkaline phosphatase-conjugated antibodies specific for RNA–DNA hybrids, and detected with a chemiluminescent substrate. Several alkaline phosphatase molecules are conjugated to each antibody. Multiple conjugated antibodies bind to each captured hybrid, resulting in substantial signal amplification. As the substrate is cleaved by the bound alkaline phosphatase, light is emitted, which is measured as relative light units (RLUs) on a luminometer. The intensity of the light emitted denotes the presence or absence of target DNA in the specimen.

Cervical specimens are collected and transported using the digene HC2 DNA Collection Device or digene Female Swab Specimen Collection Kit. Specimens are denatured using a denaturation reagent and heat. The probe mix is added, and hybridization is carried out in a hybridization microplate. Hybridized samples are transferred to a capture microplate for hybrid capture. A detection reagent is added, and a wash step is carried out. A second detection reagent is added, and detection is carried out on a luminometer.

The Hybrid Capture Modular System provides a microplate luminometer, rotary shaker, microplate heater, automated plate washer, and the Hybrid Capture Multi-Specimen Tube (MST) Vortexter that may be used for processing specimens using the digene HC2 CT/GC DNA Test.

After denaturation, the procedure can be fully automated on the Rapid Capture System through to sample detection. Detection is then carried out manually on a luminometer.

Reimbursement

The digene HC2 CT/GC DNA Test is recognized by the American Medical Association (AMA) and reimbursed using "amplified probe technique" CPT codes (when appropriate).

The digene HC2 CT/GC DNA Test is for the combined qualitative detection of Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (GC) DNA in cervical specimens. Follow-up testing using the digene HC2 CT-ID DNA Test and the digene HC2 GC-ID DNA Test is required to identify the organism(s) present in specimens that test positive with the digene HC2 CT/GC DNA Test. The digene HC2 CT/GC DNA Test is indicated for use as an initial test to identify symptomatic or asymptomatic women with Chlamydia trachomatis (CT) and/or Neisseria gonorrhoeae (GC) infection.