Which sweat test result would indicate a need to retest for CF?

Which sweat test result would indicate a need to retest for CF?

• A. >60
• B. 30-59
• C. <30
• D. Not tested

Answer: (B)

Interpreting sweat chloride results for CF hinges on established threshold ranges. A value in the indeterminate zone, 30–59 mmol/L, does not confirm or exclude cystic fibrosis by itself. Because this range can be influenced by testing conditions, technique, age, and other factors, retesting is recommended to confirm CF status. If a repeat test remains in this middle zone or if clinical suspicion remains high, additional testing such as genetic testing or a comprehensive clinical assessment is used to reach a diagnosis. Values above 60 mmol/L are strongly suggestive of CF in the right clinical context, while below 30 makes CF unlikely.

Interpreting sweat chloride results for CF hinges on established threshold ranges. A value in the indeterminate zone, 30–59 mmol/L, does not confirm or exclude cystic fibrosis by itself. Because this range can be influenced by testing conditions, technique, age, and other factors, retesting is recommended to confirm CF status. If a repeat test remains in this middle zone or if clinical suspicion remains high, additional testing such as genetic testing or a comprehensive clinical assessment is used to reach a diagnosis. Values above 60 mmol/L are strongly suggestive of CF in the right clinical context, while below 30 makes CF unlikely.