Transcortin (cortisol binding globulin)
CPT4 code
Name of the Procedure:
Transcortin Test (Cortisol Binding Globulin, CBG Test)
Summary
A transcortin test measures the levels of cortisol binding globulin (CBG) in the blood, which is important for evaluating the body’s ability to transport cortisol, a hormone essential for stress response, metabolism, and immune function.
Purpose
The test helps diagnose and monitor conditions related to abnormal cortisol levels, including adrenal gland disorders like Addison's disease and Cushing's syndrome. The goal is to determine if cortisol levels are being accurately regulated and transported in the body.
Indications
- Unexplained fatigue or weakness
- Persistent low blood pressure
- Unusual weight gain or loss
- Skin changes such as thinning or darkening
- Suspected adrenal insufficiency or hyperactivity
The test is particularly recommended for patients showing signs of hormonal imbalance or stress-related disorders.
Preparation
- Fasting for 8 hours before the test to ensure accurate results
- Informing the healthcare provider about any medications or supplements being taken, as some can affect cortisol levels
- Possibly halting steroid medications, under a doctor's direction, before the test
Procedure Description
- A blood sample is drawn from a vein, usually in the arm.
- The sample is sent to a laboratory where it is tested for CBG levels.
- The patient may need to provide additional samples if initial results are inconclusive.
The procedure requires standard phlebotomy tools and is typically performed without anesthesia as it involves only a simple blood draw.
Duration
The blood draw itself takes about 5-10 minutes. Lab results usually take a few days to a week.
Setting
The procedure is performed in a healthcare facility such as a hospital, outpatient clinic, or diagnostic laboratory.
Personnel
- Phlebotomist or nurse to draw the blood
- Laboratory technicians to analyze the blood sample
- Endocrinologist or primary care physician to interpret the results
Risks and Complications
- Minor bruising or discomfort at the needle insertion site
- Rarely, infection or excessive bleeding
- Possible light-headedness or fainting during the blood draw
Benefits
- Accurate diagnosis and monitoring of adrenal gland disorders
- Better understanding of symptoms related to cortisol imbalance
- Guidance for appropriate treatment plans
Most benefits are realized once the test results are interpreted and used to guide treatment.
Recovery
- Immediate post-procedure care includes applying pressure to the puncture site to stop bleeding
- Patients can resume normal activities almost immediately
- Follow-up appointments may be scheduled to discuss test results
Alternatives
- Salivary cortisol test: Non-invasive, measures cortisol levels at different times of the day
- 24-hour urinary free cortisol test: Measures cortisol excretion over a day
- Serum cortisol test: Direct measurement of cortisol levels in the blood
Pros and cons vary; alternative tests may be chosen based on patient condition and specific diagnostic needs.
Patient Experience
Patients typically feel a brief sting or pinch when the needle is inserted. Minor bruising or soreness may occur post-draw but is usually mild and short-lived. Comfort measures, such as applying a warm compress or taking over-the-counter pain relievers, can help manage any discomfort.