Cea is normal after thirty days of high school.

For the detection of CEA, the normal value is usually below 2.5 ng/mL. The increase of CEA may be related to many factors, including some non-malignant diseases and some cancer types, especially colorectal cancer.

According to your description, the CEA value returned to normal after ten days of examination. There may be several explanations for this situation:

1. Temporary abnormal value: CEA value fluctuates to some extent, and some abnormal values may appear in a short time, but then return to normal. So the normalization of your CEA value may be caused by temporary factors, such as some temporary inflammatory reactions.

2. Differences in detection methods: Different laboratories or detection methods may produce slightly different results. If your previous CEA values were tested in one laboratory or using a specific method, and your subsequent tests were conducted in another laboratory or using another method, this difference may lead to different results.

In any case, if you have persistent health problems or concerns, please consult your doctor for further evaluation and suggestions. They can give more accurate explanations and suggestions according to your specific situation, combined with other clinical information and test results.