Research suggests fasting before most routine blood tests may be unnecessary

A new study suggests that the long-standing medical practice of requiring patients to fast for 8 to 12 hours before blood tests may be unnecessary for most routine screenings. Research published in JAMA Internal Medicine analyzed over 9.7 million test results from more than 101,000 patients at a university hospital in South Korea between 2021 and 2023.

The findings revealed that out of 121 analyzed tests, only 10 were significantly affected by short-term fasting. While specific tests like glucose and triglycerides require fasting to ensure accuracy, most other routine tests showed minimal impact from food consumption. Furthermore, the study found that fasting for more than 12 hours provided no additional benefit for any of the tests examined.

Lead researcher Sunghwan Shin from the Asan Medical Center suggests that traditional, rigid fasting requirements should be reconsidered in favor of an approach tailored to specific analytes. Medical services like LabCorp noted that guidelines are already shifting toward non-fasting testing for many screenings, which can reduce patient discomfort and improve appointment scheduling.