Explained for patient - the investigations that may be used in diabetes and endocrinology
 

Dr Asjid Qureshi
MB ChB (Edin), MD (Lon), FRCP (Lon)
London Diabetes and Endocrinology
Consultant
Wellington Hospital and Clementine Churchill Hospital

 
 

London, UK

English / русский / العربية

 

   

 

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I N V E S T I G A T I O N S
The comments contained below apply to adult endocrinology only. With the exception of a short synacthen test, the tests listed below are best performed and interpreted by an endocrinology specialist. The details contained below are for information only.

S H O R T    S Y N A C T H E N    T E S T

When is this performed?

  • When diseases such as Addison`s disease, glucocorticoid deficiency, hypopituitarism are suspected.
What does the test involve?
  • The administration of a drug (Tetracosactrin) and the taking of blood samples to measure cortisol and ACTH levels.
Are there any side-effects?
  • Usually none
How long does the test take and is admission to hospital required?
 
  • The test takes about 1 hour and does not usually require admission
     
What should you tell your doctor?
  • If you are taking steroid medication by any route: oral, topical, inhaled, injection
  • Your allergies
 

 

 

L O N G    S Y N A C T H E N    T E S T

When is this performed?

  • To help distinguish the various causes of low steroid levels in the body.
What does the test involve?
  • The administration of a drug (Tetracosactrin at a higher dose than in the short synacthen test) and the taking of blood samples to measure cortisol and ACTH levels.
Are there any side-effects?
  • Usually none
How long does the test take and is admission to hospital required?
  • This test can may be performed in various ways. One version lasts one day and another is performed over 3 days. This test can be performed without admission to hospital.
     
What should you tell your doctor?
  • If you are taking steroid medication by any route: oral, topical, inhaled, injection
  • Your allergies
 

 

 

I N S U L I N    S T R E S S    T E S T

When is this performed?

  • When hypopituitarism is suspected.
What does the test involve?
  • The administration of insulin to lower the blood sugar and the taking of blood samples to measure glucose, cortisol and growth hormone levels.
Are there any side-effects?
  • When the blood sugar drops, you may experience sweating, palpitations and dizziness. This is temporary and expected.
How long does the test take and is admission to hospital required?
 
  • The test takes about 1 hour and does not usually require admission
     
What should you tell your doctor?
  • It is important to inform your endocrinology specialist if you have epilepsy, heart disease, glycogen storage disease or are pregnant
  • Your allergies
 

 

 

 

O R A L    G L U C O S E    T O L E R A N C E    T E S T

When is this performed?

  • In some circumstances this is required to clarify if a patient has diabetes mellitus
     
  • This test is used in pregnancy in certain patients to investigate whether a patient has gestational diabetes mellitus
     
  • This test is also used to investigate a condition called reactive hypoglycaemia
     
  • This test is used to investigate if a patient has excess growth hormone in the body (acromegaly)
What does the test involve?
  • The administration of a glucose orally and the taking of blood samples
Are there any side-effects?
  • Usually none
How long does the test take and is admission to hospital required?
 
  • The test may take 2-4 hours depending on the reason for performing it and does not usually require admission
     
What should you tell your doctor?
  • If you have diabetes mellitus
 

 

 

C O R T I S O L    D A Y    C U R V E

When is this performed?

  • To monitor the adequacy of steroid replacement in conditions like hypopituitarism and Addison`s disease
     
  • To monitor the adequacy of drug control of Cushing`s syndrome
What does the test involve?
  • The taking of blood samples to measure cortisol level.
Are there any side-effects?
  • Usually none
How long does the test take and is admission to hospital required?
 
  • The test takes about 8 hours and does not usually require admission
     
What should you tell your doctor?
  • If you are taking steroid medication by any route: oral, topical, inhaled, injection.
 

 

 

W A T E R    D E P R I V A T I O N    T E S T

When is this performed?

  • When diabetes insipidus is suspected
What does the test involve?
  • In the first half of the test, there is complete avoidance of fluid intake whilst taking intermittent blood and urine samples and weight measurements. The second half of the test involves administration of a drug (Desmopressin) and free access to fluids with urine and blood sampling.
Are there any side-effects?
  • This test may be associated with thirst. It is important that you follow instructions given to you and resist drinking in the first half. This will produce results that are easier for doctors to interpret.
How long does the test take and is admission to hospital required?
 
  • The test takes about 10 hours and does not usually require admission
     
What should you tell your doctor?
  • What medicines you take, particularly if you take Desmopressin or diuretics.
 

 

 

2 4    h o u r    u r i n e    c o l l e c t i o n

When is this performed?

  • This is required when diseases such as primary hyperparathyroidism, phaeochromocytoma and carcinoid and Cushing`s syndrome
What does the test involve?
  • Collecting the correct container (i.e. with the correct additive for the test being performed) and instructions
  • Read the instruction carefully and follow them, even if they differ from the guidance below
  • Decide which morning you will begin your collection
  • Empty your bladder that morning into the toilet and note the time. This is the "start time"
  • Your collection starts from now
  • Every drop of urine for the next 24hrs should be collected in a dry bowl or jug and poured into the container using a funnel
  • Exactly 24 hours after the start time, empty your bladder, collect this urine and place in the container
  • Your 24hr collection is complete
  • Make sure you have labelled and correctly completed the details required on the container
Are there any side-effects?
  • Usually none
How long does the test take and is admission to hospital required?
 
  • 24hrs and does not usually require admission
     
What should you tell your doctor?
  • Precisely what medication you are taking, prescribed and over the counter.
 

 

 

L O W   D O S E   D E X A M T H E S O N E   S U P P R E S S I O N   T E S T

When is this performed?

  • To clarify whether a patient has Cushing`s syndrome
What does the test involve?
  • The administration of Dexamethasone at 6hrly intervals for 2 days and the taking of blood samples to measure cortisol and ACTH levels.
Are there any side-effects?
  • Usually none
How long does the test take and is admission to hospital required?
 
  • The test takes about 3 days and does not usually require admission
     
What should you tell your doctor?
  • If you are taking steroid medication by any route: oral, topical, inhaled, injection
  • Your allergies
 

 

 

H I G H   D O S E   D E X A M T H E S O N E   S U P P R E S S I O N   T E S T

When is this performed?

  • To clarify whether a patient has Cushing`s syndrome
What does the test involve?
  • The administration of Dexamethasone at 6hrly intervals for 2 days and the taking of blood samples to measure cortisol and ACTH levels.
Are there any side-effects?
  • Usually none
How long does the test take and is admission to hospital required?
 
  • The test takes about 3 days and does not usually require admission
     
What should you tell your doctor?
  • If you are taking steroid medication by any route: oral, topical, inhaled, injection
  • Your allergies
 

 

 

B O N E    M I N E R A L    D E N S I T Y    S C A N

When is this performed?

  • To investigate whether a patient has osteoporosis or whether treatment for this has been effective
What does the test involve?
  • Lying on a couch whilst a machine arm passes over you.
Are there any side-effects?
  • This is a painless investigation. This test, like x-rays involves the use of radiation.
How long does the test take and is admission to hospital required?
 
  • A few minutes and does not usually require admission
     
What should you tell your doctor?
  • A precise list of your medication
 

 

 

M R I    S C A N

When is this performed?

  • Magnetic Resonance Imaging (MRI) is requested by an endocrinology specialist in the investigation of a variety of disorders. It is usually performed after other investigations suggest an excess or deficiency of a particular hormone(s). An MRI scan may then help locate a structural lesion to explain the hormonal findings
What does the test involve?
  • Lying on a couch that slides into a large circular shaped scanner, about 1.5m long. The scanner can be noisy and a dye may be administered through a vein to help identify abnormalities on the scan
Are there any side-effects?
  • This scan does not use radiation, like x-rays and CT scans
  • Usually none
  • The scan is painless
  • Some patients may rarely react to the dye
How long does the test take and is admission to hospital required?
 
  • The procedure may take 15-40 minutes, depending on the area being scanned, and does not usually require admission
     
What should you tell your doctor?
  • If you have a pacemaker, joint replacement or any other metal items in your body
  • If you are pregnant
  • If you are claustrophobic
  • Your allergies
 

 

 

C T    S C A N

When is this performed?

  • Computerised tomography (CT) is requested by an endocrinology specialist in the investigation of a variety of disorders. It is usually performed after other investigations suggest an excess or deficiency of a particular hormone(s). An CT scan may then help locate a structural lesion to explain the hormonal findings
What does the test involve?
  • Lying on a couch that slides into a large circular shaped scanner. A dye may be administered through a vein to help identify abnormalities on the scan
Are there any side-effects?
  • This scan does use radiation, like x-rays
  • Usually none
  • The scan is painless
  • Some patients may rarely react to the dye
How long does the test take and is admission to hospital required?
 
  • The procedure may take 10-30 minutes, depending on the area being scanned, and does not usually require admission
     
What should you tell your doctor?
  • If you are pregnant
  • If you are claustrophobic
  • Your allergies
 

 

 
 

DISCLAIMER: The information contained in the Endocrinology Specialist website is general information and not specific endocrine or diabetes advice. Patients should always consultant their physician or an endocrinology specialist. For further details please read the full disclaimer.