We receive many emails enquiring about progress. As answering these takes time away from processing submissions, please email only if absolutely necessary. We are working hard to process registration and update requests as quickly as possible.

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been endorsed by the ANZCTR. Before participating in a study, talk to your health care provider and refer to this information for consumers
Trial registered on ANZCTR

Registration number
Ethics application status
Date submitted
Date registered
Date last updated
Type of registration
Prospectively registered

Titles & IDs
Public title
Thyroid tests in people who will be taking quetiapine.
Scientific title
The effect of quetiapine on thyroid function test results measured by both immunoassay and LCMSMS, in patients prescribed quetiapine.
Secondary ID [1] 290077 0
Universal Trial Number (UTN)
Trial acronym
Linked study record
The parent study for this trial is registered on ANZCTR.org.au with registration number ACTRN12616001227482p

Health condition
Health condition(s) or problem(s) studied:
Psychosis, treated with quetiapine 300154 0
Mood disorders, treated with quetiapine 300188 0
Agitation, treated with quetiapine 300189 0
Condition category
Condition code
Mental Health 300038 300038 0 0
Mental Health 300057 300057 0 0
Mental Health 300058 300058 0 0
Other mental health disorders

Study type
Patient registry
Target follow-up duration
Target follow-up type
Description of intervention(s) / exposure
Collection of 4 blood specimens from 20 people who are about the start quetiapine and who are expected to continue treatment for at least 6 weeks. During this time, participants will take quetiapine according to their treating doctor's prescription. Doses will not be changed for the purposes of this study. The first specimen is collected before the first dose of quetiapine, then further specimens at day 1, week 3 and week 6.
Each specimen will be 7.5 millilitres, or about one and a half teaspoons volume.
Thyroid function and quetiapine will be measured in the specimens.
Intervention code [1] 295813 0
Diagnosis / Prognosis
Comparator / control treatment
No control group
Control group

Primary outcome [1] 299515 0
Comparison of Free T4 and Free T3 levels as measured by immunoassay and LC-MSMS at 3 and 6 weeks of treatment (co-primary endpoints).
Timepoint [1] 299515 0
3 weeks and 6 weeks
Secondary outcome [1] 327409 0
Secondary: quetiapine concentration as a predictor of immunoassay - LCMSMS assay difference in a mixed effects model.
Timepoint [1] 327409 0
Results from all blood specimens, at 0, 1 day, 3 weeks and 6 weeks
Secondary outcome [2] 327452 0
Exploratory: relationships between immunoassay - LCMSMS assay difference and total T3, T4, TSH and anti-thyroid antibodies.
Timepoint [2] 327452 0
Results from all blood specimens, at 0, 1 day, 3 weeks and 6 weeks

Key inclusion criteria
20 patients who are about to start taking quetiapine on a daily basis, and who are expected to still be taking it in 6 weeks time. Patients taking quetiapine for any indication may be recruited.
Minimum age
18 Years
Maximum age
No limit
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
No exclusion criteria

Study design
Natural history
Defined population
Statistical methods / analysis
Analysis of primary outcome measure from 20 participants: Initially, 2-way ANOVA or mixed effects modelling, as appropriate, followed by specific comparisons, On the assumption that fT4 population variance is similar when measured by immunoassay and LCMSMS, a paired analysis of 40 specimens will have a power of 0.87 to detect a difference of 1.25 pm/L in fT4 at p = 0.05 on 2-tailed paired t-test, Measurements of bias and 95% limits of agreement will be determined and displayed on Bland-Altman plots.
The slope of the regression line between concentrations reported by the two methodologies and the surrounding 95% confidence intervals will be calculated by linear regression. If the immunoassay and LCMSMS assay are shown to return systematically different values, an exploratory analysis will follow to estimate the effect of quetiapine concentration as a covariate in multiple regression.

Recruitment status
Date of first participant enrolment
Date of last participant enrolment
Date of last data collection
Sample size
Accrual to date
Recruitment in Australia
Recruitment state(s)
Recruitment hospital [1] 6608 0
Sir Charles Gairdner Hospital - Nedlands
Recruitment postcode(s) [1] 14215 0
6009 - Nedlands

Funding & Sponsors
Funding source category [1] 294446 0
Government body
Name [1] 294446 0
PathWest Laboratory Medicine
Address [1] 294446 0
Locked Bag 2009,
Nedlands, WA, 6009
Country [1] 294446 0
Primary sponsor type
Government body
PathWest Laboratory Medicine
Locked Bag 2009,
Nedlands, WA, 6009
Secondary sponsor category [1] 293300 0
Name [1] 293300 0
Address [1] 293300 0
Country [1] 293300 0

Ethics approval
Ethics application status
Ethics committee name [1] 295876 0
Sir Charles Gairdner Hospital Human Research Ethics Committee
Ethics committee address [1] 295876 0
2nd Floor, "A" Block,
QEII Medical Centre,
Nedlands, WA 6009
Ethics committee country [1] 295876 0
Date submitted for ethics approval [1] 295876 0
Approval date [1] 295876 0
Ethics approval number [1] 295876 0

Brief summary
Quetiapine is a commonly-prescribed drug with a good safety margin that is prescribed in psychotic illnesses, agitation and anxiety. Thyroid function is commonly checked in patients with psychotic disorders and signs of anxiety. We have observed that some patients taking quetiapine have low results on measure of free thyroid hormone level in blood, even though there is no other evidence that their thyroid function is impaired. We suspect this is because the quetiapine is interfering with the laboratory test, but it might actually be a biological effect of the quetiapine and potentially important to quetiapine’s adverse effects on metabolism.
We are asking 20 patients in whom their treating psychiatrist has already made the clinical decision to commence quetiapine as part of their management plan, to provide us with a specimen of blood to check thyroid function on 4 occasions (prior to quetiapine commencement, 1 day following commencement of quetiapine, and at weeks 3 and 6 ).
We will firstly check to see whether our impression, that free thyroid hormone tests are reading lower in patients on quetiapine by the current test, is correct. The current test is an immunoassay. Then we will use the same blood specimens to measure free thyroid hormone level by another newer, highly specific test (LCMSMS) that is not open to interference in the way immunoassays may be. A comparison of the results will tell us whether the problem is simply immunoassay interference from quetiapine.
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 68782 0
Dr Rhonda Maguire
Address 68782 0
Department of Clinical Pharmacology & Toxicology,
PathWest Laboratory Medicine,
Locked Bag 2009,
Nedlands, WA 6009
Country 68782 0
Phone 68782 0
+618 63834151
Fax 68782 0
Email 68782 0
Contact person for public queries
Name 68783 0
Dr Rhonda Maguire
Address 68783 0
Department of Clinical Pharmacology & Toxicology,
PathWest Laboratory Medicine,
Locked Bag 2009,
Nedlands, WA 6009
Country 68783 0
Phone 68783 0
+618 63834151
Fax 68783 0
Email 68783 0
Contact person for scientific queries
Name 68784 0
Dr Rhonda Maguire
Address 68784 0
Department of Clinical Pharmacology & Toxicology,
PathWest Laboratory Medicine,
Locked Bag 2009,
Nedlands, WA 6009
Country 68784 0
Phone 68784 0
+618 63834151
Fax 68784 0
Email 68784 0

No information has been provided regarding IPD availability
Summary results
No Results