Calcitonin

Measures a hormone linked to the thyroid's C cells.

For suspected medullary thyroid carcinoma and its monitoring, when indicated.

1. Check in advance whether the time of day, the day of your menstrual cycle or other timing matters.
2. Calcitonin testing may have special preparation requirements, including fasting. Check the laboratory's method instructions in advance.
3. Tell your doctor about hormone preparations and dietary supplements; do not change your treatment on your own.
4. Stay calm before the blood draw and keep to the time agreed with you.

There is no single rule. Whether you need to fast, and for how long, depends on the purpose of the test and the laboratory method; check in advance.

A specific time is generally not required. If your doctor has set a different time, follow those instructions.

• Hormone preparations and supplements
• Blood draw time or cycle phase, when relevant
• Immunoassay interference, including biotin on some platforms

Venous blood — serum or plasma, depending on the method

The blood sample is collected by a qualified staff member. The tube type, required volume, and processing and storage conditions are set by the laboratory's specific method. You do not need to store the sample yourself.

Calcitonin results are interpreted in the clinical context; a small rise can also have non-tumor causes. The meaning of a high or low result depends on age, symptoms, the method used and the reference interval.

If your result is outside the reference interval, you have symptoms, or your condition changes, contact your doctor. If symptoms are severe or develop quickly, seek emergency care.

Calcitonin interpretation depends heavily on the method, the clinical context and accompanying factors.