How do I choose between different cartridge-based diagnostic systems for field testing programs?

Choosing between cartridge-based diagnostic systems for field testing programs comes down to matching the platform to your use case, operational constraints, and total program cost—not just the headline test performance.

1) Start with the field-use question

Ask:

• What decision will the result support?
  Screening, triage, confirmatory testing, outbreak response, environmental monitoring, etc.
• Who will run the test?
  Lab-trained staff, nurses, community health workers, or non-specialists.
• Where will it be used?
  Clinic, mobile van, remote site, border checkpoint, wastewater station, farm, etc.
• How fast is “fast enough”?
  15 minutes, 1 hour, same day, or batch results are acceptable.

2) Compare analytical performance in the real setting

Don’t rely only on manufacturer claims. Look at:

• Sensitivity and specificity for your target population
• Limit of detection
• Cross-reactivity / interference
• Performance by specimen type
  Swab, whole blood, plasma, urine, saliva, stool, environmental samples
• Robustness to field conditions
  Heat, dust, vibration, humidity, cold-chain limitations

3) Assess operational fit

Cartridge systems differ a lot in practical usability:

• Sample prep complexity: none, minimal, or significant
• Hands-on time: especially important in busy or low-staff settings
• Number of steps and error risk
• Need for pipettes, centrifuges, refrigerators, or stable power
• Instrument size and portability
• Training burden
• Connectivity / LIS integration / data export
• Throughput: one sample at a time vs multi-sample batching

4) Examine cartridge and supply chain realities

A great system can fail operationally if cartridges are hard to obtain. Check:

• Cartridge cost per test
• Shelf life
• Storage temperature requirements
• Supply reliability and lead times
• Lot-to-lot consistency
• Waste disposal requirements
• Regulatory status in your country or region

5) Consider the total cost of ownership

Look beyond per-test cost:

• Instrument purchase or lease
• Maintenance/service contracts
• Calibration/verification
• Consumables and controls
• Training and onboarding
• Shipping and storage
• Downtime risk
• Replacement parts and support

6) Match throughput to program scale

A system suited for a single rural clinic may not work for a district campaign. Consider:

• Expected tests/day
• Peak demand during outbreaks or campaigns
• Turnaround time requirements
• Number of instruments needed to avoid bottlenecks

7) Evaluate data and quality requirements

For public health or regulated programs:

• Built-in QC/invalid result handling
• Audit trails
• User access controls
• Result transmission and cybersecurity
• External quality assessment compatibility
• Validation and accreditation support

8) Pilot before you commit

Run a small field evaluation using your own workflow and specimens:

• Test representative operators and sites
• Include challenging conditions
• Track invalid rates, repeats, uptime, and user errors
• Compare against the reference method
• Measure time-to-result and sample rejection rates

9) Use a scorecard

A simple decision matrix can help. Score each platform on:

• Diagnostic performance
• Ease of use
• Environmental robustness
• Throughput
• Supply chain reliability
• Cost per actionable result
• Data integration
• Support/service
• Regulatory fit

Weight the categories based on your program priorities.

Quick rule of thumb

• Choose simpler, more portable systems when access, training, and infrastructure are limited.
• Choose higher-throughput, better-integrated systems when volume, data management, and consistency matter more.
• Choose the system with the best total operational fit, not just the best lab accuracy.

If you want, I can help you build a comparison matrix template for two or three specific cartridge systems.