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Outline. 1. QuantiFERON
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1. CTCA Breakout Session:Lab Issues of In Vitro Diagnostic Testing Sally Liska, DrPH, Director
San Francisco PH Laboratory
SLiska@sfdph.org
3. Principle of the Test 1. Collect whole heparinized blood.
2. Incubate 1ml w/ 4 different antigens.
3. Measure production of interferon-? {IFN-?} using EIA {enzyme immunoassay}.
4. Compare IFN-? levels
in the 2 mycobacterial
peptide wells to the 2
controls wells.
4. Principle of the Test 1. Collect whole heparinized blood
Use Na or Li heparin (green top) tubes
Need 5 mls ? Unsatisfactory: QNS
Use 10 ml tube
Invert the tube several times to dissolve the heparin and mix with the blood
5. Principle of the Test 2. Incubate 1ml aliquots w/ 4 different antigens
Incubate 16-24 hrs
Within 12 hrs of blood collection
Four antigens:
Nil Control (PBS)
Mitogen Control
ESAT-6*
CFP-10*
*proteins which stimulate IFN-? production in those who have been infected w/ M. tb complex. Also present in M. sps kansasii, szulgai & marinum.
6. Principle of the Test 3. Measure production of interferon-? using EIA methodology.
Prepare IFN-? standard dilution series and test in duplicate
Aliquot each of the test plasma samples to microtiter plate well
Incubation time 2-3 hrs, total time 5-6 hrs
7. Principle of the Test 4. Compare IFN-? levels in the 2 mycobacterial protein wells to the 2 controls wells.
8. Inconclusive Results A. Indeterminate ? Can be due to:
1-Technical factors – incomplete washing of EIA plate, mixing Ag with blood
2-Host factors –
Peptide Ag results not more than 50% of Nil
Mitogen < 0.5, peptide results < 0.35 and Nil is <0.7 IU
B. Unsatisfactory ? Can be due to:
Lipemic or clotted specimen
9. Lab Logistics Personnel – Lab Technician, PH Micro
Test Kit
Ancillary Supplies – 24 well culture plates, pipettes, pipet tips, etc.
Equipment
Rocker for blood samples
Multi-channel pipette
Microplate shaker
Microplate washer, reader
10. Reimbursement 1. Bill another program (occupational health, jail health program, etc.)
2. Bill private insurance, submitter
3. Bill MediCal
CPT code 86849
Reimbursement amt $20.08
Submit paper bill
4. Bill Medicare
CPT code 86480
Reimbursement amt $86.58
11. Come on in – The water’s fine