Published on LMS

On completion of test run, the Test Result Screen displays the results for:

• Detection of Mycobacterium tuberculosis (Truenat MTB)
  • “DETECTED” for Positive result, Cycle Threshold (Ct) value, Colony Forming Units per milliliter (CFU/ ml)
  • “NOT DETECTED” for Negative result
  • “Valid”/ “Invalid” for test validity based on amplification of Internal Positive Control (IPC)
  • “Error” for test failure

Truenat MTB Assay results are visualized:

• During testing
• Completion of test

Test Status Screen (Figure 1)

Results visualization during testing include:

Procedure

Equipment and reagents

• Truelab Uno/ Duo/ Quattro Real Time Quantitative micro–PCR analyzer
• Truenat MTB micro-PCR kit
• Truenat MTB Rif micro-PCR kit
• Truepet fixed volume (6 μl) precision micropipette

Amplification and detection of Mycobacterium tuberculosis (MTB)

Truenat tests use Internal Quality Control to assess test validity using Internal Positive Control (IPC).

• The cartridge contains pre-loaded IPC.
• IPC is part of the full process control.
• IPC undergoes all processing steps along with specimen from extraction to amplification.
• IPC assesses the validity of the test run from sample processing to result and is illustrated in following figures (Figure 1(A) and Figure 1(B)).

Truenat cartridges are components of Trueprep AUTO v2 Universal Cartridge Based Sample Prep Kit. As shown in the figure below, each cartridge is:

• Used with Trueprep Device for DNA extraction and purification
• Disposable
• Single-use
• Preloaded with Internal Positive Control.

Truenat cartridges are used with Trueprep devices for DNA extraction and purification. The components of the cartridge are illustrated in the following figure and include:

Fluorescence Microscopy is a newer and better type of microscopy where the TB bacteria are stained using a fluorescent dye using the property of Acid Fastness. The dye will fluoresce when illuminated by UV light. When the UV light source is an LED Lamp, it is called LED fluorescent microscopy.

Here the bacilli appear as slender bright yellow fluorescent rods, standing out clearly against a dark background, as can be seen in the figure below.

Induced sputum is considered in a situation where a person is unable to provide sputum sample in sufficient quantity for Tuberculosis (TB) diagnostic test. This situation is more evident in children.

Longer oral Multi (M)/ Extensive Drug-resistant (XDR) -TB treatment is specified with a definite regime and duration.

Regimen: (18-20) Levofloxacin (Lfx), Bedaquiline (Bdq) (6 months or longer), Linezolid^# (Lzd), Clofazimine (Cfz), Cycloserine (Cs)​​ (^# dose of Lzd will be tapered to 300 mg after the initial 6–8 months of treatment)​

Once a presumptive TB patient is identified, the patient is enrolled online by a healthcare worker or doctor in Nikshay online portal. For diagnosis of Tuberculosis, the treating physician can request a test utilizing the request test option of Nikshay online portal. The step-by-step approach for test request is as follows:

Step 0: Go to the Patients Page.

Step 1: Select the “Tests” tab.

Step 2: Click the “Add Test” button.

Drug Susceptibility Testing (DST) refers to in-vitro testing using either of the phenotypic methods to determine susceptibility. Drug Resistance Testing (DRT) refers to in-vitro testing using genotypic methods (molecular techniques) to determine resistance.