Which Interpretation Method and Predicted Values to Use for Spirometry

What's happening

The CCS-200 ships with several selectable interpretation methods and predicted/reference value sets, and it's a common question which one to actually use for occupational testing. The choice isn't just a preference setting — for occupational spirometry, it's a regulatory question with a specific answer.

Interpretation methods available on the CCS-200 are ATS 1991, NLHEP, and Morris 1976 (NLHEP and Morris 1976 require the Plus Package). Separately from the interpretation method, the software also lets you select which predicted/reference value set to compare a subject's results against. For OSHA occupational spirometry, the correct reference set is NHANES III (Hankinson 1999). OSHA mandates NHANES III specifically for testing under the Cotton Dust Standard, and recommends it for other occupational spirometry programs unless a different regulation specifically calls for something else. If you're testing for occupational surveillance purposes, NHANES III (Hankinson 1999) is the set you want selected, not an older or default option the software may ship with.

Where the setting lives

1. The interpretation method and reference value set are set in the Company dialog. If you're on the Plus Package, you can also reach this through Modify Company.
2. Confirm the reference set currently selected before assuming it's already correct — this is a per-company setting, and it's worth checking rather than guessing, especially on an install that's been in place a long time or was set up by someone who's since left.
3. Chapter 10 of the CCS-200 user manual covers the full list of predicted values and interpretation methods available, if you want the underlying detail.

Before you change it — read this

Changing the interpretation method or reference value set triggers a full reanalysis of every spirogram already stored for that company. This is not a quick, reversible toggle: once the reanalysis starts, it cannot be aborted partway through. Every existing test in that company gets reinterpreted against the new reference set, which changes how those historical results are graded and displayed going forward.

Confirm you actually want this before you click through the prompt. If you're not sure whether changing the setting is the right move for a company with a long testing history, it's worth a call to us first rather than starting a reanalysis you can't stop partway through.

When to call us

• You're not sure which reference set is currently selected, or whether it's ever been changed.
• You need to change the setting on a company with a substantial history of stored spirograms and want to talk through what the reanalysis will change before you start it.
• You're setting up occupational testing for the first time and want confirmation that NHANES III (Hankinson 1999) is correctly selected before testing begins.

You can reach us at (513) 891-0868 or service@fosterinstruments.com.