Urinary Cortisol/Creatinine Ratio test

The urine cortisol/creatinine ratio is usually evaluated in the suspected cases of Cushing’s syndrome or Addison’s syndrome. 

If your body produces higher than the normal level of cortisol, then it may be an indication of Cushing’s syndrome. The symptoms of Cushing syndrome are:

• Acne
• Appearance of pink or purple streaks over the stomach and thighs 
• Weakness in muscles
• High blood sugar levels
• Obesity 
• Osteoporosis 
• Irregular menstruation cycle
• Appearance of excessive hair on the chest and face

On the other hand, Addison’s disease occurs when your adrenal glands cannot produce sufficient cortisol. The symptoms of Addison's disease are as follows:

• Sudden loss of weight 
• Uneven tone of skin with the appearance of dark patches
• Abdominal pain
• Nausea 
• Persistent tiredness 
• Pain in the muscles and joints
• Loss of interest in sexual activity (in women)
• Decreased pubic hair or hair in the armpits (in women)

No specific preparation is needed before this test. However, you must inform your doctor if you are taking any prescribed or non-prescribed medications.

Your doctor may advise you to stop taking certain medications which may interfere with the results of this test. Some of these medicines include:

• Synthetic glucocorticoids such as hydrocortisone, prednisone, prednisolone
• Oestrogen 
• Androgens
• Anti-seizure medications

A 24-hour urine sample is needed for this test. A lab technician or your doctor will give you a special container to collect the sample. 

• It is best to start sample collection from early morning. Do not collect the first urine of the day but note the time as the beginning of the 24-hour period. 
• Collect all the urine for the next 24 hours. 
• On the next day, you must collect the first urine in the morning.
• Label the container with your name, date and time of sampling and deposit it in the lab. 

In between sample collection, the container needs to be sealed appropriately and stored in a cool place, such as the refrigerator. 

For infants:

If the sample needs to be collected from an infant, you will be provided with a separate collection bag, along with the container. Place the bag over the genital area of the infant and secure it properly in place to prevent any spillage. The bag must be frequently changed after the infant has urinated in it. After sample collection, empty the contents of the bag safely into a container and submit it to the lab for testing.

Normal results

The reference ranges for the urine cortisol/creatinine ratio are as follows:

For males:

• 0-2 years: 3.0-120 mcg/g creatinine 
• 3-8 years: 2.2-89 mcg/g creatinine 
• 9-12 years: 1.4-56 mcg/g creatinine 
• 13-17 years: 1.0-42 mcg/g creatinine 
• 18 years or above: 1.0-119 mcg/g creatinine 

For females:

• 0-2 years: 3.0-120 mcg/g creatinine 
• 3-8 years: 2.2-89 mcg/g creatinine 
• 9-12 years: 1.4-56 mcg/g creatinine 
• 13-17 years: 1.0-42 mcg/g creatinine 
• 18 years or above: 0.7-85 mcg/g creatinine

Abnormal results

Higher than normal levels of cortisol in the urine indicate the presence of Cushing syndrome. Further testing may be needed to confirm the diagnosis.

It should be remembered that the test results might appear normal for individuals with mild Cushing syndrome. Other reasons for high cortisol levels could be:

• Severe stress
• Genetic disorders
• Tumour in the adrenal gland, which results in excessive production of cortisol
• Ectopic Cushing syndrome

Urine cortisol levels may also be abnormally high in patients with obesity, psychiatric disorders or alcoholism. This condition is termed as the pseudo-Cushing state. 

A lower than normal level of urine cortisol may be indicative of Addison syndrome.

Other reasons for abnormally low level of urine cortisol can be:

• Hypopituitarism (the pituitary gland does not signal the adrenal glands to release cortisol)
• Subdued functioning of the pituitary gland due to the intake of glucocorticoids or various other medications.

Disclaimer: All results must be clinically correlated with the patient’s complaints to make a complete and accurate diagnosis. The above information is provided from a purely educational point of view and is in no way a substitute for medical advice by a qualified doctor.