TB Workstation User Guide: Setup & Daily Use

This guide explains how to set up and use a TB workstation, covering the hardware connections, software configuration, and daily operating procedures you need to get accurate results. You will learn what each port and button does, how to calibrate the system, and how to troubleshoot common issues without calling for support.

What Is a TB Workstation?

A TB workstation is a laboratory bench system designed for tuberculosis testing, typically using molecular amplification methods like PCR to detect Mycobacterium tuberculosis DNA in sputum samples. It combines a thermal cycler, a computer with analysis software, and a set of pipettes and consumables in one enclosed unit. The workstation reduces contamination risk by keeping the amplification and detection steps in a closed environment, which is critical for accurate TB diagnosis.

Most TB workstations are built around a modular design: the core instrument (the thermal cycler and detector) sits on a bench, with a connected computer or touchscreen interface. The system runs a specific protocol that extracts DNA from a patient sample, amplifies it, and detects the result in under two hours. The user’s main tasks are preparing samples, loading the cartridge or plate, starting the run, and interpreting the output.

Unpacking and Setting Up the Hardware

When you first receive your TB workstation, follow these steps to get it ready:

• Place the main unit on a stable, level bench away from direct sunlight and vibration. Leave at least 15 cm of clearance on all sides for airflow.
• Connect the power cable to the back of the unit and to a grounded outlet. Do not use an extension cord unless it has a surge protector.
• Connect the computer or tablet to the unit using the provided USB or Ethernet cable. Some models use a built-in touchscreen, so no external computer is needed.
• Install the software from the supplied CD or download link. Follow the on-screen prompts, and enter the license key when asked.
• Run the system self-test from the software menu. This checks the optics, heating block, and communication ports. Wait until the self-test reports “PASS” before proceeding.

If the self-test fails, check the cable connections and restart the software. If it still fails, contact your supplier with the error code shown on the screen.

Software Setup and User Profiles

The workstation software manages user accounts, test protocols, and result storage. On first launch, create an administrator account and then add user profiles for each operator. Each profile can have its own login and permission level (for example, technician vs. supervisor).

Go to Settings > User Management to add users. For each user, set a username and password, and assign a role. The software saves all runs under the logged-in user’s name, which is important for audit trails.

Next, verify the default test protocol. The software comes with a preloaded TB detection protocol, but you should confirm the following parameters match your kit’s instructions:

• Denaturation temperature (usually 95°C)
• Annealing temperature (usually 60°C)
• Extension temperature (usually 72°C)
• Number of cycles (typically 40–45)
• Fluorescence detection channels (FAM, HEX, or ROX)

If you use a different kit, update these values in the protocol editor. Incorrect temperatures will produce invalid results.

Preparing and Loading Samples

Sample preparation is the most error-prone step. Always use the kit’s provided buffers and follow the manufacturer’s instructions for sputum decontamination and DNA extraction. Here is the general workflow:

1. Label each sample tube and the corresponding cartridge or well plate.
2. Add the extraction buffer to the sample and mix by vortexing for 10 seconds.
3. Transfer the extracted DNA to the reaction mix in a clean area, using a new pipette tip for each sample.
4. Load the reaction mix into the cartridge or plate wells. Avoid bubbles by pipetting slowly.
5. Seal the cartridge or plate with the provided film.
6. Place the cartridge into the workstation’s loading bay. Push it in until it clicks.

Always include a positive control and a negative control in each run. The positive control verifies that the reagents and machine work, and the negative control checks for contamination. The software will flag the run as invalid if the controls fail.

Running the Test and Interpreting Results

After loading, start the run from the software’s home screen. Select the test protocol, enter the sample IDs, and click Start Run. The workstation will automatically perform the amplification and fluorescence detection. A typical run takes 60–90 minutes.

When the run finishes, the software displays a table of results. Each sample shows:

• Positive – the target DNA was detected (Ct value below the threshold)
• Negative – no target DNA detected
• Invalid – the internal control failed, and the test must be repeated

The Ct (cycle threshold) value is the cycle at which fluorescence crosses the background level. A lower Ct means a higher starting amount of DNA. Most kits consider a Ct below 38 as positive, but check your kit’s manual for the exact cutoff.

To export results, go to Reports > Export and choose PDF or CSV format. The PDF includes the amplification curves and the interpretation, which is useful for patient records.

Calibration and Maintenance

Regular calibration ensures the optics and heating block remain accurate. The software includes a calibration wizard that uses a special calibration plate. Run it every six months or after any service.

Daily maintenance is simple:

• Wipe the loading bay and exterior with 70% ethanol after each run.
• Check the heating block for debris or spills.
• Empty the waste bin if your model has a built-in waste collector.

Monthly, clean the air filters on the back or side of the unit with a soft brush. If the filters are clogged, the machine may overheat and abort runs.

If the calibration fails, do not use the workstation for patient testing. Contact your service provider to adjust the optics or heating element.

Common Problems and Troubleshooting

Here are the most frequent issues users encounter and how to resolve them:

• Run aborts with a temperature error – Check that the heating block is clean and that the cartridge is seated properly. Restart the software and try again.
• No fluorescence signal – Verify that the sample contains DNA and that the correct dye channel is selected. Also check that the optical calibration is current.
• Software freezes – Close the program and restart the computer. If it happens often, reinstall the software and update the USB drivers.
• Invalid results on the negative control – This indicates contamination. Clean the work area with 10% bleach, use fresh reagents, and repeat the run.
• High Ct values on positive control – The reagents may be degraded. Check the expiration date and storage temperature of the kit.

If a problem persists, note the exact error message and the run log, then contact your supplier’s technical support. Do not attempt to open the instrument’s cover, as it contains a laser and high-voltage components.

Safety and Best Practices

Always wear gloves and a lab coat when handling samples. The workstation is a closed system, but the sample preparation area is a source of aerosols. Work in a biosafety cabinet if your lab has one.

Never use the workstation without the control samples. The software is set to reject runs without controls, but you should verify that the controls are present before starting.

Dispose of used cartridges and pipette tips in biohazard waste containers. Follow your facility’s guidelines for decontamination and waste disposal.

Keep the software updated. The manufacturer may release updates that improve accuracy or add new features. Check the supplier’s website quarterly for updates.

Frequently Asked Questions

How long does a TB test take on the workstation?

A typical run takes 60 to 90 minutes, depending on the protocol and the number of samples. The software displays the estimated time before you start the run.

Can I run multiple tests at once?

Yes, most models have a 16- or 48-well format. You can load up to that many samples in one run, but you must include at least one positive and one negative control in each run.

What does the Ct value mean?

The Ct value is the cycle at which the fluorescence from the target DNA exceeds the background. A low Ct (e.g., 20) means a high amount of TB DNA in the sample, while a high Ct (e.g., 37) means a low amount. The cutoff is usually 38, but check your kit’s manual.

How often should I calibrate the workstation?

Calibrate every six months or after any repair. If you notice inconsistent results, run the calibration wizard earlier. The software will remind you when calibration is due.

Can I use third-party reagents with the workstation?

Some workstations allow open-format protocols, but using non-certified reagents may void the warranty and affect accuracy. Always validate third-party kits with your system before routine use.

What should I do if the software says “Invalid” for a sample?

This means the internal control failed, so the result is not reliable. Repeat the test with a fresh sample and new reagents. If the problem persists, check the calibration and contact support.

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