Endocrine Diagnostics Flashcards
What are the three things that you must consider when referring a patient for a test?
The right patient
The right test
The right time
What are the main features of tests?
Tests don’t ‘give us the answer’
They are another piece of the ‘making a diagnosis’ jigsaw puzzle
The test result is added information for you to decide:
I think this patient has ‘this’ endocrine condition
I don’t think this patient has ‘this’ endocrine condition
Tests must be used and interpreted in the clinical context
What must be carried out before a test?
History
Physical examination
What is pre-test probability?
The probability of a patient having the disorder before a diagnostic test result is known
In practical terms gauged by history and examination findings
What must you ask yourself before carrying out a diagnostic test?
If I do this test, how will it change the way that I manage this patient?
Why must you carefully consider sending patients for tests?
Cost to NHS
Worries the patient
When should you perform radiology in endocrinology?
After the biochemistry
Incidental-omas can be found on imaging
What is a static blood test?
Snap shot in time of hormone levels in the patient’s when the blood test was taken
Why is time of day for test important?
Many hormones are secreted according to a 24 hour circadian cycle
If measured at the wrong time of day the hormone can appear to be low
Give an example of a circadian hormone
cortisol levels in the blood
Cortisol levels in the blood are highest first thing in the morning
If we had done the blood tests at 4pm after clinic
Blood cortisol levels will be low – in everyone
Therefore cannot be interpreted
What do static blood tests not take into account?
Pulsatility of hormones
What are the two types of dynamic blood tests?
Suppression test
Stimulation test
What must be considered before dynamic blood tests?
Logistics: staff, hospital visit, cost
Patient acceptability: e.g. some tests can take a long time, multiple blood samples taken
Safety e.g. insulin tolerance test
What do you do when your pre-test probability and test results are not concordant?
Troubleshoot
How do you troubleshoot a patient?
Look at your patient
Conditions are not fixed but evolve over time
Has something changed?
Look at the pre-test probability
I do/don’t think the patient has the condition
Interpret the result in this context
Look at the logistics of the test
Wrong patient
Time of day/pulsatility not taken into account
Sample not handled properly
e.g. prolonged time to lab resulting in hormone degradation in the tube
Lab error e.g. faulty assay
If nothing explain it:
Repeat the test
