Florida Bureau of Public Health laboratories
Nucleic Acid Amplification Test for Mycobacterium tuberculosis complex (MTBC)
The TB real-time PCR (rtPCR) nucleic acid amplification test (NAAT) for TB insertion sequence 6110 (IS6110) test.
Analyte(s)
TB insertion sequence 6110 (IS6110)
Test Code
3140
Testing Location
Testing Department
Mycobacteriology (TB)
Pre-approval Required?
Yes, for out-of-state submissions
Required Forms
BPHL Test Requisition, DH1847
(not needed if orders are placed via electronic order)
Minimum Volume
At least 5 mL of unprocessed specimen, or
At least 0.5 – 1 mL of processed specimen
Turn Around time
48 hours after receipt at the laboratory
Supply Ordering
Supplies may be requested from your servicing laboratory. Supplies ordered from the BPHL should only be used for specimen sent to the BPHL for testing.
Collection Media
50 mL sterile conical
Specimen Sources
Respiratory specimens (5 ml minimum) or CSF. Processed specimens are acceptable.
Non-respiratory sources are accepted with prior approval from TB control
Specimen Labeling
Specimen must be labeled with at least two unique patient identifiers, e.g., name and DOB.
Information on the specimen must match the requisition and/or test order.
Special SPecimen Preparation
Gastric lavage specimens must be neutralized with 100 mg of sodium carbonate if the time between collection and processing exceeds 4 hours
Storage Conditions
Store specimens refrigerated at 2 – 8° C until time of shipment.
Packaging and Shipping
Specimens can be shipped within the 2-28° C temperature range, except for urine specimens.
Urine must be shipped refrigerated (2 – 8° C). Processed urine sediments may be shipped within the 2-28° C temperature range and must be clearly marked on the requisition as “Processed”.
Separate specimens to prevent cross-contamination.
unsatisfactory specimen
1) Formalin fixed or paraffin-embedded tissues
2) No patient identification on specimen tube
3) No specimen observed in specimen container
4) Specimen damaged or leaked entirely in transit
5) Gastric aspirates that have not been neutralized
6) Urine specimens arriving outside of acceptable temperature range
7) AFB Smear cannot be performed on blood specimens
8) Samples cross contaminated due to sample leaking in transit
Interferences and Limitations
Specimens contaminated by blood. A positive result indicates the DNA of Mycobacterium tuberculosis complex is present does not necessarily indicate viable organism.
Reference Range
Negative for MTBC by real-time PCR.
Result Indicator
Positive: Positive for MTBC DNA
Neg: Negative for MTBC DNA
Indeterminate: Inconclusive for MTBC DNA
Reference lab
Paraffin embedded tissue can be sent to CDC Infectious Disease Pathology Branch (IDPB) for NAAT testing. Requires prior approval from the TB Physician Network.
Reflex testing
Positive specimens will reflex to GeneXpert MTB/RIF, Deeplex assay