Performed

Monday - Friday

Methodology

Enzyme-Linked Immunosorbent Assay (ELISA)

Reported

Routine: 3 - 5 days

Synonyms

  • TB Screening Test
  • Latent TB
  • Latent Tuberculosis
  • LTBI
  • M. tuberculosis
  • Mycobacteria
  • Mycobacterium tuberculosis (MTB)
  • PPD
  • QuantiFERON Gold Plus
  • IFN-Gamma
  • IGRA
  • Interferon-Gamma Release Assay
  • Microbiology Serology

Performing Lab

Microbiology

Add-on Eligibility

NO

Specimen Type

Blood

Specimen Volume

1 mL into each of the 4 QFT-Plus Blood Collection Tubes

Collection Container

1 set of 4 QFT-Plus Blood Collection Tubes
  • 1 Quantiferon Nil Tube (QFT-Plus Gray Top Vacutainer)
  • 1 Quantiferon TB1 Tube (QFT-Plus Green Top Vacutainer)
  • 1 Quantiferon TB2 Tube (QFT-Plus Yellow Top Vacutainer)
  • 1 Quantiferon Mitogen Tube (QFT-Plus Purple Top Vacutainer)

Unacceptable Conditions

  1. More than one specimen within 7 days
  2. Specimens that have been improperly collected, stored, or transported
  • The level of blood in any of the 4 tubes is outside of the black indicator mark
  • Blood samples collected into QFT-Plus Blood Collection Tubes and stored longer than 16 hours at room temperature
  • Alternative tube types or incomplete tube sets
  1. QFT-Plus Blood Collection Tubes that were not shaken immediately after collection
  2. QFT-Plus Blood Collection Tubes where overly vigorous shaking caused gel disruption
  3. QFT-Plus Blood Collection Tubes previously incubated or centrifuged
  4. Unlabeled or mislabeled specimens

Storage/Transport Temperature

Transport Instructions      
Collection Location Transport Temperature Processing Required Timeframe
ED/Inpatient Room Temperature Immediately after filling the tubes, shake them 10 times Specimen must be received by the lab within 16 hours of collection
Laboratory/Outpatient/Off-Site Room Temperature Immediately after filling the tubes, shake them 10 times Specimen must be received by the lab within 16 hours of collection

Storage: Room Temperature (prior to incubation and separation from cells)

Stability (from collection to initiation)

Stability:
Prior to incubation at 37°C:
  • Room Temperature: 16 hours
After incubation and separation from cells:
  • Refrigerated: 28 days

Laboratory Storage: Refrigerated
Laboratory Retention: 7 days

Collection Instructions

Labeling Instructions:
  1. When labeling blood tubes, leave a small window visible for the lab to assess the fill volume and sample integrity.  Ensure that the barcode is in the correct orientation and is not covering the black fill-level indicator bar.
          

Collection Instructions:
  1. Collect 1 mL of blood by venipuncture directly into each of the QFT-Plus Blood Collection Tubes.
  • As 1 mL tubes draw blood relatively slowly, keep the tube on the needle for 2 – 3 seconds once the tube appears to have completed filling.
  • The black mark on the side of the tubes indicates the validated fill-volume range. If the level of blood in any tube is outside of the indicator mark, a new blood sample should be obtained.
  • If a butterfly needle is being use to collect blood, a “purge” tube should be used to ensure that the tubing is filled with blood prior to the QFT-Plus Blood Collection Tubes being used.
  1. Immediately after filling the tubes, shake them 10 times just firmly enough to make sure the entire inner surface of the tube is coated with blood.  This will dissolve antigens on the tube walls.  Over vigorous shaking may cause gel disruption and lead to aberrant results.

Reference Interval

Quantiferon TB Gold Plus Reference Ranges    
Nil
(IU/mL)		 TB1 minus Nil
(IU/mL)		 TB2 minus Nil
(IU/mL)		 Mitogen minus Nil
(IU/mL)		 QFT-Plus Result Interpretation
≤8.0 ≥0.35 and ≥25% of Nil Any Any Positive M. tuberculosis infection likely
Any ≥0.35 and ≥25% of Nil
<0.35 or
≥0.35 and <25% of Nil		 <0.35 or
≥0.35 and <25% of Nil		 ≥0.50 Negative M. tuberculosis infection NOT likely
<0.35 or
≥0.35 and <25% of Nil		 <0.35 or
≥0.35 and <25% of Nil		 <0.50 Uninterpretable Likelihood of M. tuberculosis infection cannot be determined
>8.0 Any

Interpretive Data

Diagnosing or excluding tuberculosis disease and assessing the probability of latent tuberculosis infection requires a combination of epidemiological, historical, medical, and diagnostic findings that should be taken into account when interpreting QuantiFERON-TB Gold in Tube assay results.
Ordering

Performed

Monday - Friday

Methodology

Enzyme-Linked Immunosorbent Assay (ELISA)

Reported

Routine: 3 - 5 days

Synonyms

  • TB Screening Test
  • Latent TB
  • Latent Tuberculosis
  • LTBI
  • M. tuberculosis
  • Mycobacteria
  • Mycobacterium tuberculosis (MTB)
  • PPD
  • QuantiFERON Gold Plus
  • IFN-Gamma
  • IGRA
  • Interferon-Gamma Release Assay
  • Microbiology Serology

Performing Lab

Microbiology

Add-on Eligibility

NO
Collection

Specimen Type

Blood

Specimen Volume

1 mL into each of the 4 QFT-Plus Blood Collection Tubes

Collection Container

1 set of 4 QFT-Plus Blood Collection Tubes
  • 1 Quantiferon Nil Tube (QFT-Plus Gray Top Vacutainer)
  • 1 Quantiferon TB1 Tube (QFT-Plus Green Top Vacutainer)
  • 1 Quantiferon TB2 Tube (QFT-Plus Yellow Top Vacutainer)
  • 1 Quantiferon Mitogen Tube (QFT-Plus Purple Top Vacutainer)

Unacceptable Conditions

  1. More than one specimen within 7 days
  2. Specimens that have been improperly collected, stored, or transported
  • The level of blood in any of the 4 tubes is outside of the black indicator mark
  • Blood samples collected into QFT-Plus Blood Collection Tubes and stored longer than 16 hours at room temperature
  • Alternative tube types or incomplete tube sets
  1. QFT-Plus Blood Collection Tubes that were not shaken immediately after collection
  2. QFT-Plus Blood Collection Tubes where overly vigorous shaking caused gel disruption
  3. QFT-Plus Blood Collection Tubes previously incubated or centrifuged
  4. Unlabeled or mislabeled specimens

Storage/Transport Temperature

Transport Instructions      
Collection Location Transport Temperature Processing Required Timeframe
ED/Inpatient Room Temperature Immediately after filling the tubes, shake them 10 times Specimen must be received by the lab within 16 hours of collection
Laboratory/Outpatient/Off-Site Room Temperature Immediately after filling the tubes, shake them 10 times Specimen must be received by the lab within 16 hours of collection

Storage: Room Temperature (prior to incubation and separation from cells)

Stability (from collection to initiation)

Stability:
Prior to incubation at 37°C:
  • Room Temperature: 16 hours
After incubation and separation from cells:
  • Refrigerated: 28 days

Laboratory Storage: Refrigerated
Laboratory Retention: 7 days

Collection Instructions

Labeling Instructions:
  1. When labeling blood tubes, leave a small window visible for the lab to assess the fill volume and sample integrity.  Ensure that the barcode is in the correct orientation and is not covering the black fill-level indicator bar.
          

Collection Instructions:
  1. Collect 1 mL of blood by venipuncture directly into each of the QFT-Plus Blood Collection Tubes.
  • As 1 mL tubes draw blood relatively slowly, keep the tube on the needle for 2 – 3 seconds once the tube appears to have completed filling.
  • The black mark on the side of the tubes indicates the validated fill-volume range. If the level of blood in any tube is outside of the indicator mark, a new blood sample should be obtained.
  • If a butterfly needle is being use to collect blood, a “purge” tube should be used to ensure that the tubing is filled with blood prior to the QFT-Plus Blood Collection Tubes being used.
  1. Immediately after filling the tubes, shake them 10 times just firmly enough to make sure the entire inner surface of the tube is coated with blood.  This will dissolve antigens on the tube walls.  Over vigorous shaking may cause gel disruption and lead to aberrant results.
Result Interpretation

Reference Interval

Quantiferon TB Gold Plus Reference Ranges    
Nil
(IU/mL)		 TB1 minus Nil
(IU/mL)		 TB2 minus Nil
(IU/mL)		 Mitogen minus Nil
(IU/mL)		 QFT-Plus Result Interpretation
≤8.0 ≥0.35 and ≥25% of Nil Any Any Positive M. tuberculosis infection likely
Any ≥0.35 and ≥25% of Nil
<0.35 or
≥0.35 and <25% of Nil		 <0.35 or
≥0.35 and <25% of Nil		 ≥0.50 Negative M. tuberculosis infection NOT likely
<0.35 or
≥0.35 and <25% of Nil		 <0.35 or
≥0.35 and <25% of Nil		 <0.50 Uninterpretable Likelihood of M. tuberculosis infection cannot be determined
>8.0 Any

Interpretive Data

Diagnosing or excluding tuberculosis disease and assessing the probability of latent tuberculosis infection requires a combination of epidemiological, historical, medical, and diagnostic findings that should be taken into account when interpreting QuantiFERON-TB Gold in Tube assay results.

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