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The TrueNAT laboratory should maintain a document/ records of Truelab and Trueprep usage and maintenance using the logs and/ or checklist. This helps to:

• Maintain record of the health of the instrument for user and manufacturer
• Reduce risks of accidents due to faulty instrument
• Identify user re-training needs
• Reduce instrument downtime.

Representative documents to maintain record for use and maintenance are shown in table 1(A) - (B) and figure below.

Like any other laboratory instrument, the TrueNAT machine needs a periodic maintenance.

Maintenance of Truelab and Trueprep instruments includes:

• Cleaning the instrument
• Disinfecting the surfaces
• Cleaning the spillages
• Discarding the used consumables
• Calibrations
• Replacement of parts
• Flush protocol
• Data backup
• Troubleshooting errors, alerts, warning messages

Frequency of maintenance:

The limitations of TrueNAT Assays are:

“Indeterminate” result on completion of the test run with TrueNAT MTB-Rif Dx means Polymerase Chain Reaction (PCR) melting temperature (Tm) values did not meet the requirements for Rif resistance determination.

Implications

• The initial result of Mycobacterium tuberculosis “DETECTED’ (Truenat MTB) is the bacteriological confirmation of TB.
• TrueNAT MTB Rif Dx did not provide information on resistance to Rif.

Troubleshooting TrueNAT MTB Rif Dx “Indeterminate”

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

The extra-pulmonary samples (Non-sputum) can also be processed and used for MTB and Rif diagnosis using Truenat. The processing of various extra-pulmonary samples is described below.

Reagents required:

Trueprep AUTO MTB Sample Pre-treatment Pack for sample processing

• Reagents stable for two years (2-40°C) or one month (temperatures up to 45°C)
• Avoid exposure to light or elevated temperatures
• Do not freeze

Steps in processing of non-sputum samples

Samples collected for TrueNAT tests are tested immediately (if collected at TrueNAT facility) or transported on the same day to nearest linked TrueNAT facility.

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:

TrueNAT MTB and TrueNAT MTB Rif Dx Assay are intended to be used for detection of Mycobacterium tuberculosis bacteria (for TB diagnosis) and to detect resistance to rifampicin (Rif), respectively.

Positioning of TrueNAT MTB and TrueNAT MTB Rif Dx Assay

TrueNAT MTB and TrueNAT MTB Rif Dx Assay are suitable as point-of-care tests for use in peripheral laboratories and microscopy centres due to the following operational features: