Do the six endocrine tests require fasting for blood drawing

The six endocrine tests usually require fasting blood tests. Fasting requirements are mainly related to the susceptibility of indicators such as blood glucose and insulin in the examination items to dietary influences, while other influencing factors include examination time, medication interference, exercise status, and individual differences.

1. Blood glucose indicators:

Fasting blood glucose is the core item of the six endocrine functions. After eating, blood glucose levels will rapidly increase, which may lead to false overestimation of results. It is required to fast for at least 8 hours and not even drink sugary drinks. If glycated hemoglobin is detected simultaneously, fasting is not necessary.

2. Insulin testing:

Insulin levels directly reflect pancreatic function, and postprandial insulin secretion increases 2-5 times. Under fasting conditions, basal insulin levels are more stable and can accurately determine whether there is insulin resistance or insufficient secretion.

3. Best time:

It is recommended to have blood drawn between 8-10 am, when hormone secretion in the body is at baseline. Some hormones, such as cortisol, have a circadian rhythm, and missing the optimal time may require repeated testing.

4. Drug interference:

Oral hypoglycemic drugs and steroid drugs need to be informed in advance. For example, metformin may affect insulin testing, and glucocorticoids may interfere with adrenocorticotropic hormone results.

3. Exercise effects:

Increased adrenaline levels after intense exercise may indirectly affect multiple hormone levels. High intensity exercise should be avoided 24 hours before the examination, and sit quietly for 15 minutes before blood draw to maintain a stable state. After completing the blood draw, it is important to eat promptly to avoid low blood sugar and prioritize high protein foods such as eggs and milk. Maintain a normal diet for the first 3 days before the examination and avoid deliberate dieting. Long term fasting may cause distortion of hormone levels. Pregnant women should pay attention to the testing of six sex hormones at specific times during the menstrual cycle, which is different from the fasting requirement of routine endocrine tests. The elderly or diabetes patients can take snacks to replenish energy immediately after blood drawing.