LT-Microscopy & NAAT

Some Cartridge-based Nucleic Acid Amplification Test (CBNAAT) machine errors will indicate test failure without Error Codes.

Error: Invalid

Problem: 

Sample Processing Control (SPC) failed.

Origin: 

Polymerase Chain Reaction (PCR) was inhibited due to food particles or blood in the sample.

Solution:  

Laboratory Technician (LT) needs to collect another specimen, if necessary.

Prevention: 

Error - 2014, 3074, 3075 and 1001, in the Cartridge-based Nucleic Acid Amplification Test (CBNAAT) machine are related to ‘Heating Component Related Issues’.

Problem:

Temperature/ Heater Failure

Origins:

• High temperature in module 
• Heater component failure 
• Broken fan 
• Dust on filter near the fan

Troubleshooting:

In the CBNAAT Dx System window:

During the use of the Cartridge-based Nucleic Acid Amplification Test (CBNAAT) machine, Error- 2008 and 2009 may appear on the screen and needs troubleshooting.

Problem:

2008: Pressure reading exceeds the maximum

2009: Syringe pressure is below the protocol limit

Figure: Error 2008

Origins:

One of the common problems encountered while using the CBNAAT machine is the non-detection of the module.

Usually, there is a loss of communication between modules and software, leading to non-detection.

Origins:

• Ethernet connection between Personal Computer (PC) and CBNAAT is bad
• Power supply issue (main power or Universal Power Supply (UPS) fluctuations)
• Bad connection points between gateway board and modules
• Too high room temperature 

Solutions:

If the barcode scanner is not working, enter the cartridge barcode manually (Figure):

• Step 1: Click on “Create Test”
• Step 2: A dialogue box - Scan Cartridge Barcode will appear. Click on “Manual Entry”
• Step 3: Manually type the 2-line numbers of the cartridges

Figure: Process for Manual Entry of the Cartridge Barcode

The most common situations that need troubleshooting while using CBNAAT are:

• Hardware or instrument problems
• Failures without error codes 
• Failures with error codes 

Troubleshooting Approach

1. In case of an issue, a message will be displayed (often with an error code). 
2. Check if the error affects one particular module. 
3. Refer to the CBNAAT user manual and follow the recommended corrective action.

The Cartridge-based Nucleic Acid Amplification Test (CBNAAT) test has some limitations such as:

The test results of the Cartridge-based Nucleic Acid Amplification Test (CBNAAT) assay are displayed in the ‘View Results’ window, of the CBNAAT software.

For visualizing the results after the test is completed:

The assay needs to be repeated by using a new cartridge if one of the following test results occur:

INVALID: An INVALID result indicates that Sample Processing Control (SPC) failed. The sample was not properly processed, or Polymerase Chain Reaction (PCR) was inhibited.

ERROR: An ERROR indicates that Probe Check Control (PCC) failed, and the assay was aborted possibly due to the reaction chamber being filled improperly, a reagent probe integrity, syringe pressure issues, or failure of the CBNAAT module.

The following procedures are recommended when processing various body fluids with the Cartridge-based Nucleic Acid Amplification Test (CBNAAT):

Bronchoalveolar Lavage (BAL): 

Processing of BAL for CBNAAT assay is given here. However, it is important that each laboratory optimizes this protocol to minimize the error rate.

If the BAL volume is sufficient (approx. 5 ml), centrifuge and dissolve sediment into 1 ml sterile phosphate buffer/ saline, then add sample reagent in a 1:2 ratio.