What a fasting reading captures
A fasting reading is taken after a period without caloric intake and is used in clinical testing because it reduces the immediate effect of a recent meal. Home fasting readings can also help reveal recurring morning patterns, but diagnosis belongs with validated clinical testing.
What a post-meal reading captures
A post-meal reading shows what happened after a specific eating event. It is influenced by carbohydrate amount, meal composition, timing, activity, medication and individual physiology.
Consistency makes data more interpretable
- Use the timing your health care team recommends.
- When comparing meals, measure at consistent time points.
- Record enough context to explain outliers.
- Don't compare a fasting value from one day with a random post-meal value from another and treat the difference as a trend.
Targets are individualized.
CDC publishes typical targets used for many adults with diabetes, but age, pregnancy, medications, comorbidities and hypoglycemia risk can change the target your clinician sets.
Sources & verification
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