QUANTIFERON GOLD PLUS (QFT PLUS)
Test Code: LAB9907
CPT Code: 86480
Interface Code
QGOLD
Synonym
MYCOBACTERIUM TUBERCULOSIS, QUANTIFERON GOLD, QFT-Plus, QFT, Interferon-gamma Release Assay (IGRA) for Mycobacterium tuberculosis, IGRA, TB Gold
Specimen Type
Whole blood Lithium Heparin or Sodium Heparin tube (NO GEL or PST) DO NOT CENTRIFUGE
or
Blood collected into QFT-Plus Blood Collection Kit
or
Blood collected into QFT-Plus Blood Collection Kit
Specimen Container
Green top Lithium Heparin tube or Sodium Heparin (NO GEL or PST)
or
QFT-Plus Blood Collection tubes/kit
DO NOT CENTRIFUGE
or
QFT-Plus Blood Collection tubes/kit
DO NOT CENTRIFUGE
Specimen Handling
SINGLE TUBE collection:
1. Collect whole blood into Lithium or Sodium Green top tube (6 mL/min 5 mL) with no gel; specimen for testing cannot be submitted in multiple green top tubes so be sure to use a 10 mL sized tube for this collection
2. Keep specimen at room temperature for at least 15 min but not more than 3 hours after collection
3. Refrigerate specimen once room temperature requirements are met and submit to lab; specimens can be refrigerated for up to 48 hours
4. On receipt at the lab the blood will be transferred to the QFT-Plus Blood Collection Tubes and will be incubated in accordance with the QTB Gold SOP
If DIRECTLY COLLECTING into QFT-PLUS IN-TUBE COLLECTION KIT (this is a general overview - please follow instructions with the kit):
Collection kit includes (4) different tubes: Nil, TB-1, TB-2, Mitogen
1. Be sure collection kit is at room temperature before doing the blood collection
2. The (4) tubes can be collected in the following order (though not required): Nil, TB 1, TB 2, Mitogen
3. Each tube requires 1 mL of blood and has a black indicator on the tube (the indicator allows for 0.8 - 1.2 mL volume variation); under and overfilled tubes will be rejected. Note: The QFT tubes fill slowly compared to other vacuum tubes.
4. Immediately after filling, shake the four tubes 10 times firmly but not vigorously (frothing is expected)
5. Incubation at 37C of the tubes follows for 16-24 hours
Note: To avoid rejections or invalid test results, be sure to follow collection steps as outlined for the QFT collection kit (if collecting Green top no gel tube, it must be collected into 1 tube with a minimum of 5 mL). This test does not allow for variation with collection volume (each QFT tube in the set must have 1 mL). Special reagents are embedded within each of the QFT collection tubes and the whole blood volume to reagent is critical for valid testing.
After incubation, the QFT tube set is centrifuged to obtain plasma for testing.
1. Collect whole blood into Lithium or Sodium Green top tube (6 mL/min 5 mL) with no gel; specimen for testing cannot be submitted in multiple green top tubes so be sure to use a 10 mL sized tube for this collection
2. Keep specimen at room temperature for at least 15 min but not more than 3 hours after collection
3. Refrigerate specimen once room temperature requirements are met and submit to lab; specimens can be refrigerated for up to 48 hours
4. On receipt at the lab the blood will be transferred to the QFT-Plus Blood Collection Tubes and will be incubated in accordance with the QTB Gold SOP
If DIRECTLY COLLECTING into QFT-PLUS IN-TUBE COLLECTION KIT (this is a general overview - please follow instructions with the kit):
Collection kit includes (4) different tubes: Nil, TB-1, TB-2, Mitogen
1. Be sure collection kit is at room temperature before doing the blood collection
2. The (4) tubes can be collected in the following order (though not required): Nil, TB 1, TB 2, Mitogen
3. Each tube requires 1 mL of blood and has a black indicator on the tube (the indicator allows for 0.8 - 1.2 mL volume variation); under and overfilled tubes will be rejected. Note: The QFT tubes fill slowly compared to other vacuum tubes.
4. Immediately after filling, shake the four tubes 10 times firmly but not vigorously (frothing is expected)
5. Incubation at 37C of the tubes follows for 16-24 hours
Note: To avoid rejections or invalid test results, be sure to follow collection steps as outlined for the QFT collection kit (if collecting Green top no gel tube, it must be collected into 1 tube with a minimum of 5 mL). This test does not allow for variation with collection volume (each QFT tube in the set must have 1 mL). Special reagents are embedded within each of the QFT collection tubes and the whole blood volume to reagent is critical for valid testing.
After incubation, the QFT tube set is centrifuged to obtain plasma for testing.
Volume
Green top: 6 mL (must be in one tube/cannot be multiple tubes)
Minimum Volume
Green Top Tube: 5 mL
Temperature
Green Lithium Heparin: Refrigerate (stable 48 hours)
QFT Plus Tubes: Room Temperature (stable 16 hours)
QFT Plus Tubes: Room Temperature (stable 16 hours)
Unacceptable Conditions
Less than 5 mL whole blood lithium or sodium heparin, frozen specimen, PST tube, or centrifuged specimens. QFT tubes that are over 16 hours old. QFT tubes that are not at room temperature.
Methodology
ELISA
Additional Information
Note: Due to supply chain shortages the large green top tubes may not be available. The QuantiFERON-QTB Gold In-Tube Collection Kit will be supplied if large green top tubes are not available. Carefully follow instructions included with the kit.
Stability
Note: This stability noted below relates to the initial collection step ONLY.
Lithium/Sodium Heparin Stability:
Room Temperature: Keep at Room Temperature a minimum of 15 min after collection up to 3 hours then refrigerate.
Refrigerated: Once Room Temperature requirement complete (noted above) refrigerate for up to 48 hours.
Frozen: Not acceptable
QFT-Plus Blood Collection Tube Set Stability:
Room Temperature: 16 hours (follow collection instructions closely)
Refrigerated: Not acceptable
Frozen: Not acceptable
Lithium/Sodium Heparin Stability:
Room Temperature: Keep at Room Temperature a minimum of 15 min after collection up to 3 hours then refrigerate.
Refrigerated: Once Room Temperature requirement complete (noted above) refrigerate for up to 48 hours.
Frozen: Not acceptable
QFT-Plus Blood Collection Tube Set Stability:
Room Temperature: 16 hours (follow collection instructions closely)
Refrigerated: Not acceptable
Frozen: Not acceptable
Reference Range Information
Reference values are dependent upon methodology/instrumentation, check final report for current reference values
Turn Around Time
1-7 days
Performing Site
Pacific Diagnostic Laboratories
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