Ordering Recommendations

The QuantiFERON test detects the release of IFN-gamma released by whole blood lymphocytes after incubation with tuberculin purified protein derivative and phytohemagglutinin.
 
The test is intended for screening asymptomatic individuals who may be at risk for latent tuberculosis (recent immigrants, prisoners and prison/jail employees) or TB exposure (military, hospital personnel). In these settings it is equivalent but no better than skin testing.
 
QuanitFERON testing may be more specific than skin testing when screening individuals with a history of prior BCG vaccination.
 
It is NOT recommended for use in patients with symptoms of active TB (known to cause decreased IFN-G responses), contacts of patients with active TB, immunosuppressed patients, patients with diabetes, silicosis, chronic renal failure, leukemia, lymphoma, head/neck cancer, lung cancer, s/p gastrectomy or jejunoileal bypass. In these situations skin testing is recommended.
 

Available Stat

No

Performing Lab

Immunology

Performed

Tuesday and Friday (day shift)

Methodology

Chemiluminescent Immunoassay

Reported

5-7 days

Synonyms

  • Tuberculosis
  • TB
  • TB skin test
  • Interferon gamma
  • IFN gamma

Sample Type

Blood

Collect

Requires special collection kit available from central laboratory containing:
 
QFT-Nil Control tube Gray cap, white ring
QFT-TB1 Antigen tube Green cap, white ring
QFT-TB2 Antigen tube Yellow cap, white ring
QFT-Mitogen Control tube Purple cap, white ring

Note: It is mandatory the tubes be filled correctly within the black line indicated on the tubes, underfilled or overfilled tubes will be rejected by lab.
 

Amount to Collect

4 mL blood, place 1 mL of blood into each tube in the collection kit

Remarks

A set of four QuantiFERON-TB Gold Plus tubes (Gray cap/white ring, Green cap/white ring, Yellow cap/white ring and Purple cap/white ring) must be collected at the same time, with 1mL of blood in each tube. 

Note: It is mandatory the tubes be filled correctly as underfilled or overfilled tubes will be rejected by the lab. 

INPATIENT:
COLLECT SAMPLE 3 AM – 6:30 PM ON MONDAY – FRIDAY ONLY. DO NOT COLLECT SAMPLE ON WEEKEND OR UCSF OBSERVED HOLIDAYS

OUTPATIENTS:
COLLECT BETWEEN 7 AM – 6 PM ON MONDAY – FRIDAY ONLY BY UCSF LABORATORY STAFF AT OUR OUTPATIENT FACILITIES. DO NOT COLLECT SAMPLE ON WEEKEND OR UCSF OBSERVED HOLIDAYS.
 
1. For Parnassus and Mission Bay inpatient only, pick up collection kits from Laboratory Central Processing. 
 
2. Collect 1 ml of blood by venipuncture directly into each of the four tubes (Nil, TB1 Antigen, TB2 Antigen, Mitogen). Fill each tube up to the black mark indicated on the collection tube. Under or overfilling of the tubes may lead to erroneous results.
 
3.  Mix the tubes by shaking firmly and vertically for 10 times and label tubes appropriately.

4.  Please verify that all four collection tubes are collected with appropriate amount of blood (blood volume is within the black line indicated on the tube). Please do not stick label all around the tube, but allow sample level and black line visible to ease testing in the laboratory.

5. These are TIME SENSITIVE samples, please deliver the tubes to the Laboratory Central Processing immediately.


 

Stability (from collection to initiation)

Samples need to be incubated at China Basin as soon as possible after collection (within 16 hours of collection).

Storage/Transport Temperature

Room Temperature

Unacceptable Conditions

Frozen or refrigerated samples.  Improperly collected samples. Overfilled or underfilled tubes received.

Grossly hemolyzed, icteric or lipemic samples as well as samples with obvious microbial contamination.

Test Code

QFTBP

Performing Lab

Immunology

Specimen Preparation

Accession the samples immediately upon receipt and send to Immunology Lab at China Basin at room temperature. Samples received after 6:30pm or 7pm, please send them with Microbiology Lab courier to China Basin Mircrobiology Lab. Please reject samples collected after 6:30pm that missed 8:30pm courier run.

Exception: Accept samples collected outside of "3am – 6:30pm Monday - Friday" from patients admitted for a kidney transplant at Parnassus only. The tubes will be delivered by kidney transplant unit staff to Central Processing Lab at Parnassus to accession. Send the samples to Microbiology Lab at China Basin for incubation and processing.

Please verify that all four collection tubes are collected with appropriate amount of blood (blood volume is within the black line indicated on the tube). Please do not stick label all around the tube, but allow sample level and black line visible to ease testing in the laboratory.

 

Unacceptable Conditions

Frozen or refrigerated samples.  Improperly collected samples. Overfilled or underfilled tubes received.

Grossly hemolyzed, icteric or lipemic samples as well as samples with obvious microbial contamination.

Stability (from collection to initiation)

Samples need to be incubated at China Basin as soon as possible after collection (within 16 hours of collection).

Storage/Transport Temperature

Room Temperature

Units

IU/mL

Reference Interval

Negative

 

Interpretive Data

Results Interpretation:
 
Nil = QNIL (IU/mL) TB1 - Nil = QTB1 (IU/mL) TB2-Nil = QTB2 (IU/mL) Mitogen - Nil = QMIT (IU/mL) QTF-Plus Result and Interpretation
≤ 8.0 < 0.35 OR ≥ 0.35 and <25% of Nil value < 0.35 OR ≥ 0.35 and <25% of Nil value ≥ 0.5 Negative
M. tuberculosis infection NOT likely
≤ 8.0 ≥ 0.35 AND ≥ 25% of Nil value Any Any Positive
M. tuberculosis infection likely
≤ 8.0 Any ≥ 0.35 AND ≥ 25% of Nil value Any Positive
M. tuberculosis infection likely
≤ 8.0 < 0.35 OR ≥ 0.35 and <25% of Nil value < 0.35 OR ≥ 0.35 and <25% of Nil value < 0.5 Indeterminate
Likelihood of M. tuberculosis infection cannot be determined
> 8.0 Any Any Any Indeterminate
Likelihood of M. tuberculosis infection cannot be determined

A negative QuantiFERON-TB Gold Plus result does not preclude the possibility of Mycobacterium tuberculosis infection or tuberculosis disease. Falsely negative results can be due to the stage of infection, conditions that affect immune functions, improper blood sample collection or handling of the specimen.

A positive QuantiFERON-TB Gold Plus result indicates that a Mycobacterium tuberculosis infection is very likely. False-positive QuantiFERON-TB Gold Plus result may occur due to improper preanalytical processing of the QuantiFERON-TB Gold Plus tubes, prior infection with certain other mycobacteria or biologic variability. Positive results should be confirmed with other clinical, exposure, and laboratory findings.

Test is not interpretable with indeterminate result. An indeterminate QuantiFERON-TB Gold Plus result suggests possible preanalytic error or individual patient related factors.

CPT Codes

86481

LOINC Codes

71775-1 - QUANTIFERON®-TB GOLD PLUS Panel code   
71776-9 - NIL    
64084-7 - TB1-NIL    
88517-8 - TB2-NIL
71774-4 - MITOGEN-NIL    
71773-6 - QUANTIFERON®-TB GOLD PLUS Result

Available Stat

No

Ordering Recommendations

The QuantiFERON test detects the release of IFN-gamma released by whole blood lymphocytes after incubation with tuberculin purified protein derivative and phytohemagglutinin.
 
The test is intended for screening asymptomatic individuals who may be at risk for latent tuberculosis (recent immigrants, prisoners and prison/jail employees) or TB exposure (military, hospital personnel). In these settings it is equivalent but no better than skin testing.
 
QuanitFERON testing may be more specific than skin testing when screening individuals with a history of prior BCG vaccination.
 
It is NOT recommended for use in patients with symptoms of active TB (known to cause decreased IFN-G responses), contacts of patients with active TB, immunosuppressed patients, patients with diabetes, silicosis, chronic renal failure, leukemia, lymphoma, head/neck cancer, lung cancer, s/p gastrectomy or jejunoileal bypass. In these situations skin testing is recommended.
 

Test Code

QFTBP

Performing Lab

Immunology

Performed

Tuesday and Friday (day shift)

Methodology

Chemiluminescent Immunoassay

Remarks

A set of four QuantiFERON-TB Gold Plus tubes (Gray cap/white ring, Green cap/white ring, Yellow cap/white ring and Purple cap/white ring) must be collected at the same time, with 1mL of blood in each tube. 

Note: It is mandatory the tubes be filled correctly as underfilled or overfilled tubes will be rejected by the lab. 

INPATIENT:
COLLECT SAMPLE 3 AM – 6:30 PM ON MONDAY – FRIDAY ONLY. DO NOT COLLECT SAMPLE ON WEEKEND OR UCSF OBSERVED HOLIDAYS

OUTPATIENTS:
COLLECT BETWEEN 7 AM – 6 PM ON MONDAY – FRIDAY ONLY BY UCSF LABORATORY STAFF AT OUR OUTPATIENT FACILITIES. DO NOT COLLECT SAMPLE ON WEEKEND OR UCSF OBSERVED HOLIDAYS.
 
1. For Parnassus and Mission Bay inpatient only, pick up collection kits from Laboratory Central Processing. 
 
2. Collect 1 ml of blood by venipuncture directly into each of the four tubes (Nil, TB1 Antigen, TB2 Antigen, Mitogen). Fill each tube up to the black mark indicated on the collection tube. Under or overfilling of the tubes may lead to erroneous results.
 
3.  Mix the tubes by shaking firmly and vertically for 10 times and label tubes appropriately.

4.  Please verify that all four collection tubes are collected with appropriate amount of blood (blood volume is within the black line indicated on the tube). Please do not stick label all around the tube, but allow sample level and black line visible to ease testing in the laboratory.

5. These are TIME SENSITIVE samples, please deliver the tubes to the Laboratory Central Processing immediately.


 

Collect

Requires special collection kit available from central laboratory containing:
 
QFT-Nil Control tube Gray cap, white ring
QFT-TB1 Antigen tube Green cap, white ring
QFT-TB2 Antigen tube Yellow cap, white ring
QFT-Mitogen Control tube Purple cap, white ring

Note: It is mandatory the tubes be filled correctly within the black line indicated on the tubes, underfilled or overfilled tubes will be rejected by lab.
 

Amount to Collect

4 mL blood, place 1 mL of blood into each tube in the collection kit

Sample Type

Blood

Unacceptable Conditions

Frozen or refrigerated samples.  Improperly collected samples. Overfilled or underfilled tubes received.

Grossly hemolyzed, icteric or lipemic samples as well as samples with obvious microbial contamination.

Specimen Preparation

Accession the samples immediately upon receipt and send to Immunology Lab at China Basin at room temperature. Samples received after 6:30pm or 7pm, please send them with Microbiology Lab courier to China Basin Mircrobiology Lab. Please reject samples collected after 6:30pm that missed 8:30pm courier run.

Exception: Accept samples collected outside of "3am – 6:30pm Monday - Friday" from patients admitted for a kidney transplant at Parnassus only. The tubes will be delivered by kidney transplant unit staff to Central Processing Lab at Parnassus to accession. Send the samples to Microbiology Lab at China Basin for incubation and processing.

Please verify that all four collection tubes are collected with appropriate amount of blood (blood volume is within the black line indicated on the tube). Please do not stick label all around the tube, but allow sample level and black line visible to ease testing in the laboratory.

 

Units

IU/mL

Reference Interval

Negative

 

Interpretive Data

Results Interpretation:
 
Nil = QNIL (IU/mL) TB1 - Nil = QTB1 (IU/mL) TB2-Nil = QTB2 (IU/mL) Mitogen - Nil = QMIT (IU/mL) QTF-Plus Result and Interpretation
≤ 8.0 < 0.35 OR ≥ 0.35 and <25% of Nil value < 0.35 OR ≥ 0.35 and <25% of Nil value ≥ 0.5 Negative
M. tuberculosis infection NOT likely
≤ 8.0 ≥ 0.35 AND ≥ 25% of Nil value Any Any Positive
M. tuberculosis infection likely
≤ 8.0 Any ≥ 0.35 AND ≥ 25% of Nil value Any Positive
M. tuberculosis infection likely
≤ 8.0 < 0.35 OR ≥ 0.35 and <25% of Nil value < 0.35 OR ≥ 0.35 and <25% of Nil value < 0.5 Indeterminate
Likelihood of M. tuberculosis infection cannot be determined
> 8.0 Any Any Any Indeterminate
Likelihood of M. tuberculosis infection cannot be determined

A negative QuantiFERON-TB Gold Plus result does not preclude the possibility of Mycobacterium tuberculosis infection or tuberculosis disease. Falsely negative results can be due to the stage of infection, conditions that affect immune functions, improper blood sample collection or handling of the specimen.

A positive QuantiFERON-TB Gold Plus result indicates that a Mycobacterium tuberculosis infection is very likely. False-positive QuantiFERON-TB Gold Plus result may occur due to improper preanalytical processing of the QuantiFERON-TB Gold Plus tubes, prior infection with certain other mycobacteria or biologic variability. Positive results should be confirmed with other clinical, exposure, and laboratory findings.

Test is not interpretable with indeterminate result. An indeterminate QuantiFERON-TB Gold Plus result suggests possible preanalytic error or individual patient related factors.

Synonyms

  • Tuberculosis
  • TB
  • TB skin test
  • Interferon gamma
  • IFN gamma

Storage/Transport Temperature

Room Temperature

Stability (from collection to initiation)

Samples need to be incubated at China Basin as soon as possible after collection (within 16 hours of collection).

Reported

5-7 days

CPT Codes

86481

LOINC Codes

71775-1 - QUANTIFERON®-TB GOLD PLUS Panel code   
71776-9 - NIL    
64084-7 - TB1-NIL    
88517-8 - TB2-NIL
71774-4 - MITOGEN-NIL    
71773-6 - QUANTIFERON®-TB GOLD PLUS Result
Ordering

Ordering Recommendations

The QuantiFERON test detects the release of IFN-gamma released by whole blood lymphocytes after incubation with tuberculin purified protein derivative and phytohemagglutinin.
 
The test is intended for screening asymptomatic individuals who may be at risk for latent tuberculosis (recent immigrants, prisoners and prison/jail employees) or TB exposure (military, hospital personnel). In these settings it is equivalent but no better than skin testing.
 
QuanitFERON testing may be more specific than skin testing when screening individuals with a history of prior BCG vaccination.
 
It is NOT recommended for use in patients with symptoms of active TB (known to cause decreased IFN-G responses), contacts of patients with active TB, immunosuppressed patients, patients with diabetes, silicosis, chronic renal failure, leukemia, lymphoma, head/neck cancer, lung cancer, s/p gastrectomy or jejunoileal bypass. In these situations skin testing is recommended.
 

Available Stat

No

Performing Lab

Immunology

Performed

Tuesday and Friday (day shift)

Methodology

Chemiluminescent Immunoassay

Reported

5-7 days

Synonyms

  • Tuberculosis
  • TB
  • TB skin test
  • Interferon gamma
  • IFN gamma
Collection

Sample Type

Blood

Collect

Requires special collection kit available from central laboratory containing:
 
QFT-Nil Control tube Gray cap, white ring
QFT-TB1 Antigen tube Green cap, white ring
QFT-TB2 Antigen tube Yellow cap, white ring
QFT-Mitogen Control tube Purple cap, white ring

Note: It is mandatory the tubes be filled correctly within the black line indicated on the tubes, underfilled or overfilled tubes will be rejected by lab.
 

Amount to Collect

4 mL blood, place 1 mL of blood into each tube in the collection kit

Remarks

A set of four QuantiFERON-TB Gold Plus tubes (Gray cap/white ring, Green cap/white ring, Yellow cap/white ring and Purple cap/white ring) must be collected at the same time, with 1mL of blood in each tube. 

Note: It is mandatory the tubes be filled correctly as underfilled or overfilled tubes will be rejected by the lab. 

INPATIENT:
COLLECT SAMPLE 3 AM – 6:30 PM ON MONDAY – FRIDAY ONLY. DO NOT COLLECT SAMPLE ON WEEKEND OR UCSF OBSERVED HOLIDAYS

OUTPATIENTS:
COLLECT BETWEEN 7 AM – 6 PM ON MONDAY – FRIDAY ONLY BY UCSF LABORATORY STAFF AT OUR OUTPATIENT FACILITIES. DO NOT COLLECT SAMPLE ON WEEKEND OR UCSF OBSERVED HOLIDAYS.
 
1. For Parnassus and Mission Bay inpatient only, pick up collection kits from Laboratory Central Processing. 
 
2. Collect 1 ml of blood by venipuncture directly into each of the four tubes (Nil, TB1 Antigen, TB2 Antigen, Mitogen). Fill each tube up to the black mark indicated on the collection tube. Under or overfilling of the tubes may lead to erroneous results.
 
3.  Mix the tubes by shaking firmly and vertically for 10 times and label tubes appropriately.

4.  Please verify that all four collection tubes are collected with appropriate amount of blood (blood volume is within the black line indicated on the tube). Please do not stick label all around the tube, but allow sample level and black line visible to ease testing in the laboratory.

5. These are TIME SENSITIVE samples, please deliver the tubes to the Laboratory Central Processing immediately.


 

Stability (from collection to initiation)

Samples need to be incubated at China Basin as soon as possible after collection (within 16 hours of collection).

Storage/Transport Temperature

Room Temperature

Unacceptable Conditions

Frozen or refrigerated samples.  Improperly collected samples. Overfilled or underfilled tubes received.

Grossly hemolyzed, icteric or lipemic samples as well as samples with obvious microbial contamination.
Processing

Test Code

QFTBP

Performing Lab

Immunology

Specimen Preparation

Accession the samples immediately upon receipt and send to Immunology Lab at China Basin at room temperature. Samples received after 6:30pm or 7pm, please send them with Microbiology Lab courier to China Basin Mircrobiology Lab. Please reject samples collected after 6:30pm that missed 8:30pm courier run.

Exception: Accept samples collected outside of "3am – 6:30pm Monday - Friday" from patients admitted for a kidney transplant at Parnassus only. The tubes will be delivered by kidney transplant unit staff to Central Processing Lab at Parnassus to accession. Send the samples to Microbiology Lab at China Basin for incubation and processing.

Please verify that all four collection tubes are collected with appropriate amount of blood (blood volume is within the black line indicated on the tube). Please do not stick label all around the tube, but allow sample level and black line visible to ease testing in the laboratory.

 

Unacceptable Conditions

Frozen or refrigerated samples.  Improperly collected samples. Overfilled or underfilled tubes received.

Grossly hemolyzed, icteric or lipemic samples as well as samples with obvious microbial contamination.

Stability (from collection to initiation)

Samples need to be incubated at China Basin as soon as possible after collection (within 16 hours of collection).

Storage/Transport Temperature

Room Temperature
Result Interpretation

Units

IU/mL

Reference Interval

Negative

 

Interpretive Data

Results Interpretation:
 
Nil = QNIL (IU/mL) TB1 - Nil = QTB1 (IU/mL) TB2-Nil = QTB2 (IU/mL) Mitogen - Nil = QMIT (IU/mL) QTF-Plus Result and Interpretation
≤ 8.0 < 0.35 OR ≥ 0.35 and <25% of Nil value < 0.35 OR ≥ 0.35 and <25% of Nil value ≥ 0.5 Negative
M. tuberculosis infection NOT likely
≤ 8.0 ≥ 0.35 AND ≥ 25% of Nil value Any Any Positive
M. tuberculosis infection likely
≤ 8.0 Any ≥ 0.35 AND ≥ 25% of Nil value Any Positive
M. tuberculosis infection likely
≤ 8.0 < 0.35 OR ≥ 0.35 and <25% of Nil value < 0.35 OR ≥ 0.35 and <25% of Nil value < 0.5 Indeterminate
Likelihood of M. tuberculosis infection cannot be determined
> 8.0 Any Any Any Indeterminate
Likelihood of M. tuberculosis infection cannot be determined

A negative QuantiFERON-TB Gold Plus result does not preclude the possibility of Mycobacterium tuberculosis infection or tuberculosis disease. Falsely negative results can be due to the stage of infection, conditions that affect immune functions, improper blood sample collection or handling of the specimen.

A positive QuantiFERON-TB Gold Plus result indicates that a Mycobacterium tuberculosis infection is very likely. False-positive QuantiFERON-TB Gold Plus result may occur due to improper preanalytical processing of the QuantiFERON-TB Gold Plus tubes, prior infection with certain other mycobacteria or biologic variability. Positive results should be confirmed with other clinical, exposure, and laboratory findings.

Test is not interpretable with indeterminate result. An indeterminate QuantiFERON-TB Gold Plus result suggests possible preanalytic error or individual patient related factors.

Administrative

CPT Codes

86481

LOINC Codes

71775-1 - QUANTIFERON®-TB GOLD PLUS Panel code   
71776-9 - NIL    
64084-7 - TB1-NIL    
88517-8 - TB2-NIL
71774-4 - MITOGEN-NIL    
71773-6 - QUANTIFERON®-TB GOLD PLUS Result
Complete View

Available Stat

No

Ordering Recommendations

The QuantiFERON test detects the release of IFN-gamma released by whole blood lymphocytes after incubation with tuberculin purified protein derivative and phytohemagglutinin.
 
The test is intended for screening asymptomatic individuals who may be at risk for latent tuberculosis (recent immigrants, prisoners and prison/jail employees) or TB exposure (military, hospital personnel). In these settings it is equivalent but no better than skin testing.
 
QuanitFERON testing may be more specific than skin testing when screening individuals with a history of prior BCG vaccination.
 
It is NOT recommended for use in patients with symptoms of active TB (known to cause decreased IFN-G responses), contacts of patients with active TB, immunosuppressed patients, patients with diabetes, silicosis, chronic renal failure, leukemia, lymphoma, head/neck cancer, lung cancer, s/p gastrectomy or jejunoileal bypass. In these situations skin testing is recommended.
 

Test Code

QFTBP

Performing Lab

Immunology

Performed

Tuesday and Friday (day shift)

Methodology

Chemiluminescent Immunoassay

Remarks

A set of four QuantiFERON-TB Gold Plus tubes (Gray cap/white ring, Green cap/white ring, Yellow cap/white ring and Purple cap/white ring) must be collected at the same time, with 1mL of blood in each tube. 

Note: It is mandatory the tubes be filled correctly as underfilled or overfilled tubes will be rejected by the lab. 

INPATIENT:
COLLECT SAMPLE 3 AM – 6:30 PM ON MONDAY – FRIDAY ONLY. DO NOT COLLECT SAMPLE ON WEEKEND OR UCSF OBSERVED HOLIDAYS

OUTPATIENTS:
COLLECT BETWEEN 7 AM – 6 PM ON MONDAY – FRIDAY ONLY BY UCSF LABORATORY STAFF AT OUR OUTPATIENT FACILITIES. DO NOT COLLECT SAMPLE ON WEEKEND OR UCSF OBSERVED HOLIDAYS.
 
1. For Parnassus and Mission Bay inpatient only, pick up collection kits from Laboratory Central Processing. 
 
2. Collect 1 ml of blood by venipuncture directly into each of the four tubes (Nil, TB1 Antigen, TB2 Antigen, Mitogen). Fill each tube up to the black mark indicated on the collection tube. Under or overfilling of the tubes may lead to erroneous results.
 
3.  Mix the tubes by shaking firmly and vertically for 10 times and label tubes appropriately.

4.  Please verify that all four collection tubes are collected with appropriate amount of blood (blood volume is within the black line indicated on the tube). Please do not stick label all around the tube, but allow sample level and black line visible to ease testing in the laboratory.

5. These are TIME SENSITIVE samples, please deliver the tubes to the Laboratory Central Processing immediately.


 

Collect

Requires special collection kit available from central laboratory containing:
 
QFT-Nil Control tube Gray cap, white ring
QFT-TB1 Antigen tube Green cap, white ring
QFT-TB2 Antigen tube Yellow cap, white ring
QFT-Mitogen Control tube Purple cap, white ring

Note: It is mandatory the tubes be filled correctly within the black line indicated on the tubes, underfilled or overfilled tubes will be rejected by lab.
 

Amount to Collect

4 mL blood, place 1 mL of blood into each tube in the collection kit

Sample Type

Blood

Unacceptable Conditions

Frozen or refrigerated samples.  Improperly collected samples. Overfilled or underfilled tubes received.

Grossly hemolyzed, icteric or lipemic samples as well as samples with obvious microbial contamination.

Specimen Preparation

Accession the samples immediately upon receipt and send to Immunology Lab at China Basin at room temperature. Samples received after 6:30pm or 7pm, please send them with Microbiology Lab courier to China Basin Mircrobiology Lab. Please reject samples collected after 6:30pm that missed 8:30pm courier run.

Exception: Accept samples collected outside of "3am – 6:30pm Monday - Friday" from patients admitted for a kidney transplant at Parnassus only. The tubes will be delivered by kidney transplant unit staff to Central Processing Lab at Parnassus to accession. Send the samples to Microbiology Lab at China Basin for incubation and processing.

Please verify that all four collection tubes are collected with appropriate amount of blood (blood volume is within the black line indicated on the tube). Please do not stick label all around the tube, but allow sample level and black line visible to ease testing in the laboratory.

 

Units

IU/mL

Reference Interval

Negative

 

Interpretive Data

Results Interpretation:
 
Nil = QNIL (IU/mL) TB1 - Nil = QTB1 (IU/mL) TB2-Nil = QTB2 (IU/mL) Mitogen - Nil = QMIT (IU/mL) QTF-Plus Result and Interpretation
≤ 8.0 < 0.35 OR ≥ 0.35 and <25% of Nil value < 0.35 OR ≥ 0.35 and <25% of Nil value ≥ 0.5 Negative
M. tuberculosis infection NOT likely
≤ 8.0 ≥ 0.35 AND ≥ 25% of Nil value Any Any Positive
M. tuberculosis infection likely
≤ 8.0 Any ≥ 0.35 AND ≥ 25% of Nil value Any Positive
M. tuberculosis infection likely
≤ 8.0 < 0.35 OR ≥ 0.35 and <25% of Nil value < 0.35 OR ≥ 0.35 and <25% of Nil value < 0.5 Indeterminate
Likelihood of M. tuberculosis infection cannot be determined
> 8.0 Any Any Any Indeterminate
Likelihood of M. tuberculosis infection cannot be determined

A negative QuantiFERON-TB Gold Plus result does not preclude the possibility of Mycobacterium tuberculosis infection or tuberculosis disease. Falsely negative results can be due to the stage of infection, conditions that affect immune functions, improper blood sample collection or handling of the specimen.

A positive QuantiFERON-TB Gold Plus result indicates that a Mycobacterium tuberculosis infection is very likely. False-positive QuantiFERON-TB Gold Plus result may occur due to improper preanalytical processing of the QuantiFERON-TB Gold Plus tubes, prior infection with certain other mycobacteria or biologic variability. Positive results should be confirmed with other clinical, exposure, and laboratory findings.

Test is not interpretable with indeterminate result. An indeterminate QuantiFERON-TB Gold Plus result suggests possible preanalytic error or individual patient related factors.

Synonyms

  • Tuberculosis
  • TB
  • TB skin test
  • Interferon gamma
  • IFN gamma

Storage/Transport Temperature

Room Temperature

Stability (from collection to initiation)

Samples need to be incubated at China Basin as soon as possible after collection (within 16 hours of collection).

Reported

5-7 days

CPT Codes

86481

LOINC Codes

71775-1 - QUANTIFERON®-TB GOLD PLUS Panel code   
71776-9 - NIL    
64084-7 - TB1-NIL    
88517-8 - TB2-NIL
71774-4 - MITOGEN-NIL    
71773-6 - QUANTIFERON®-TB GOLD PLUS Result

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