What are PPA and NPA?

Positive percent agreement (PPA) and negative percent agreement (NPA) describe how often a new test agrees with a comparator method on positive and negative results. They are used when the comparator is not a perfect reference standard, and are typically reported with 95% confidence intervals.

Do you calculate agreement for each target in a panel?

Yes. For multiplex panels we support target-level analysis, so each organism or marker has its own agreement estimates and confidence intervals.

Service 03

Clinical Validation & Evidence Strategy

Clinical validity is where a test's claims meet real patient specimens. We help design comparator studies aligned to intended use, analyze agreement at the target level, investigate discordance and state claims and limitations clearly.

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Scope of support

What this engagement covers

Clinical comparator study design
Specimen sourcing and intended-use alignment
Target-level PPA/NPA and confidence intervals
Discordance investigation
Polymicrobial analysis
Clinical validity claims and limitations

What you can expect

Study designs that match the population and specimen types in the intended use
Statistically sound agreement estimates with confidence intervals
Transparent handling of discordant and polymicrobial results

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