Preferred Sample Type
Suitable Specimen Types
- Serum
Sample Processing in Laboratory
Routine
Sample Preparation
Separate and store at -20
Turnaround Time
21 daysSample Stability
Store separated serum at -20ºC
Prednisolone / Prednisolone Absorption / Metabolism Test
General Information
Prednisolone is a steroid drug used for the treatment of a number of conditions including asthma. It does not meet the normal criteria for therapeutic drug monitoring as there is no clear relationship between plasma levels and therapeutic effect. However its measurement is increasingly regarded of value as a check of compliance, and possibly to investigate patients who metabolize the drug at an abnormal rate. Patients with severe asthma are a group in which measurement may be particularly useful.
Prednisolone, prednisone, cortisone and cortisol are measured using Tandem Mass Spectrometry (LC-MS/MS) following diethyl ether extraction of steroids from plasma. Deuterated prednisolone (D6) and cortisol (D4) are used as the internal standards.
Patient Preparation
Patient preparation depends on whether an absorption test is being performed. No patient preparation is required if a single prednisolone measurement is required. If an absorption test is being performed then the following protocol should be used.
PREDNISOLONE METABOLISM TEST
Procedure:
- Collect 5ml blood for baseline measurement into a plain/ gel tube (“clotted sample”) at approximately 8.30am.
Label “Pre-Prednisolone – 8.30am” - Administer standardised dose (0.5mg/kg) of Prednisolone. E.g. 60kg = 30mg. “this need to be directly observed by a medical staff” at 8.30 am.
- Collect 5ml samples of blood at 9.00am, 10.00 am, 11.00 am, 12.00pm.
- Please label accurately each sample time on the tube.
Sample Requirements:
- Serum (yellow or red top tube)
- Minimum volume of each sample = 0.5ml serum
- 1 off samples can be used to identify poor compliance with medication.
Request Form:
- One request form should be completed for all samples.
- Request ‘PREDNISOLONE ABSORPTION TEST’. F.A.O: Mrs Joanne Duffy.
- State time of sample on each bottle.
- Transport to Clinical Biochemistry, BHH.
Notes:
- Please ensure patient does not take their morning dose of prednisolone prior to starting the test.
Please record the following clinical information and send to the laboratory with the samples:
Notes
Aim: To assess prednisolone metabolism in steroid dependent asthmatics Justification: Small group of asthmatics remain symptomatic despite long term treatment with oral corticosteroids “prednisolone”, with major implication in terms of steroid induced side effects. The cause of this lack of effect could be due to poor adherence, malabsorption, rapid metabolism or genetically mediated resistance to steroids. The aim of this test is to assess the cause of the apparent lack of responsiveness to steroids in a patient.
Additionally, PREDAT may be requested for a short synacthen test in patients that are on prednisolone or other steroids. In these cases, both the 0 and 30 minutes specimen should be booked in for PREDAT and NOT cortisol. Cortisol by mass spectrometry is required in these patients due to interferences in the automated cortisol method.
Reference Range
N/A
Specifications
- EQA Scheme?: No
-
EQA Status:
No applicable scheme