Abnormal glucose tolerance and the 50-gram glucose challenge test in Cystic fibrosis

Saba Sheikh, A. Russell Localio, Andrea Kelly, Ronald C. Rubenstein

Research output: Contribution to journalArticlepeer-review

6 Scopus citations


Diabetes has emerged as a major co-morbidity in cystic fibrosis (CF). The 75 g oral glucose tolerance test (OGTT) is used to screen for CF-related diabetes (CFRD) but is inconvenient, and adherence to screening is poor. The 50 g glucose challenge test (GCT) is shorter, performed non-fasting, and may serve to pre-screen the subset of individuals requiring confirmatory OGTT. We performed a pilot study in twenty-seven CF individuals across the glucose tolerance spectrum to test whether the GCT could identify subjects with abnormal glucose tolerance defined as 2-h OGTT glucose ≥7.8 mmol/L (2 h-AGT) or 1-h defined as 1-hr OGTT glucose ≥11.1 mmol/L (1 h-AGT). A GCT threshold of 8.1 mmol/L was 73% sensitive and 63% specific for 2hr-AGT and 80% sensitive and 65% specific for 1hr-AGT. Therefore, a screening GCT may reduce need for confirmatory OGTT for identifying AGT but a larger study is warranted to identify a robust cutoff for CFRD.

Original languageEnglish
Pages (from-to)696-699
Number of pages4
JournalJournal of Cystic Fibrosis
Issue number5
StatePublished - Sep 2020


  • Cystic Fibrosis
  • Cystic Fibrosis Related Diabetes
  • Glucose challenge test
  • Oral glucose tolerance test


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