Preferred Sample Type


Suitable Specimen Types

  • Serum
  • EDTA Plasma
  • Li Hep Plasma
A minimum of 500 µl of plasma/serum is required.

Specimen Transport

First class post

Sample Processing in Laboratory

Place sample in toxicology rack.

Sample Preparation

None required

Turnaround Time

3 days.

Sample Stability

Keep refrigerated. 4 degrees.


General Information

Gliclazide is a sulphonylurea derivative that has been used clinically since 1972 as an oral hypoglycaemic agent. Adult doses are usually in the range of 30 - 320 mg daily in one or two divided portions. 

Adverse reactions to gliclazide therapy may include nausea, heartburn, headache, allergic skin reactions, haematologic abnormalities and cholestatic jaundice. 

Please note, this test is for the quantitative measurement of gliclazide in blood. Screening for use of gliclazide (and other sulphonylurea drugs) in patients presenting with hypoglycaemia of unknown cause may be performed using the Sulphonylurea Screen.

Patient Preparation

For TDM, sample should be taken prior to dose. If toxicity is suspected, take sample at earliest opportunity


Gliclazide measured by HPLC-DAD.


Reference Range

Daily oral administration of 80 mg gliclazide to 144 subjects resulted in steady–state plasma concentrations of 0.3 to 8.2 mg/L (mean 2.5). (Clarke's Analysis of Drugs & Poisons, Third Edition)

Copyright heftpathology 2013, 2014, 2015, 2016, 2017, 2018

HTA licence number is 12366

Protection of Personal Information – Laboratory Medicine comply with the Trust Data Protection Policy and have procedures in place to allow the Directorate and it’s employees to comply with the Data Protection Act 1998 and associated best practice and guidance.

The Trust Laboratories at Heartlands Hospital, Good Hope Hospital and Solihull Hospital were awarded UKAS (United Kingdom Accreditation Service) accreditation to the internationally recognised ISO 15189 standard in May 2015. For a list of accredited tests and other information please visit the test database
Tests not appearing on this scope are either under consideration or in the process of accreditation and so currently remain outside of our scope of accreditation. However, these tests have been validated to the same high standard as accredited tests and are performed by the same trained and competent staff.

For further information contact Louise Fallon, Quality Manager, 0121 424 1235