- Medicines and Healthcare products Regulatory Agency
- 22 June 2016
- 22 June 2016
- Alert type:
- Medical device alert
False low results may occur in a range of clinical chemistry tests in specimens drawn from patients treated with N-acetylcysteine (NAC) due to the interference with specific assays utilised by Siemens ADVIA instruments.
Action by pathology staff
- Establish if affected Siemens ADVIA Chemistry and Dimension/Dimension Vista assays are used in your laboratory.
Action by all healthcare personnel managing patients on these drugs
- Ensure all relevant members of staff receive the manufacturer’s Field Safety Notices (FSN) and that they understand the problem and the advice given by the manufacturer.
- Continue to only use affected assays on patients that are not being treated with NAC.
- Ensure bloods are taken prior to NAC treatment.
- When requesting any of the affected assays, record on the request if the patient is being treated with NAC.
- Monitor the MHRA website or subscribe to email alerts for any further FSNs on this issue.
Deadlines for actions
Actions underway: 28 June 2016
Actions complete: 22 August 2016
List of assays affected:
|Assay||Test code||Catalogue number||Siemens material number (SMN)||Lot number|
|ADVIA chemistry products affected by N-acetylcysteine (NAC) only|
|Glucose oxidase,concentrated reagents||GLUO_c||74721||10335872|
|ADVIA chemistry products affected by N-acet** ylcysteine (NAC) and metamizole**|
|Uric acid, concentratedreagents||UA_c||74715||10335873|
|Dimension products affected by N-acet** ylcysteine (NAC) and metamizole**|
|Dimension Vista products affected by N-acet** ylcysteine (NAC) and metamizole**|
Note: Dimension® URCA and Dimension Vista® URCA are not Trinder reaction assays but they do produce peroxide and are susceptible to metamizole interference.
Siemens has issued Field Safety Notices regarding false low results on a number of assays carried out by their ADVIA Dimension/Dimension Vista instruments. This is due to the interference of NAC in affected assays that use the Trinder reaction. NAC is the accepted antidote for acetaminophen toxicity.
Patients being treated with metamizole/dipyrone/novaminsulfone are also affected but these products are not licensed for use in the UK. Metamizole is an anti-inflammatory anti-pyretic drug that is not licensed in some countries because of the potential for nephrotoxicity.
Investigations suggest that the peroxidase used in the Trinder reaction employed by affected assays leads to interference with NAC, causing falsely low recovery leading to misinterpretation of their physiological status. Similar assays from other manufacturers may also be affected by NAC interference and this is currently under investigation.
The manufacturer is updating the instructions for use for the ADVIA assays.
Authorised representative contacts
Siemens Healthcare Diagnostics Limited
Newton House, Sir William Siemens Square
Tel: 01908 282 433
If you are responsible for cascading these alerts in your organisation, these are our suggested distribution lists.
Trusts (NHS boards in Scotland)
CAS and SABS (NI) liaison officers for onward distribution to all relevant staff including:
- A&E consultants
- A&E departments
- A&E directors
- A&E nurses
- Adult intensive care units
- All wards
- Anaesthesia, directors of
- Anaesthetic medical staff
- Anaesthetic nursing staff
- Biomedical science departments
- Chief pharmacists
- Clinical governance leads
- Clinical pathologists
- Clinical pathology directors
- Hospital pharmacies
- Hospital pharmacists
- Intensive care medical staff/paediatrics
- Intensive care nursing staff (adult)
- Intensive care nursing staff (paediatric)
- Intensive care units
- Intensive care, directors of
- Medical directors
- Paediatric intensive care units
- Paediatric medicine, directors of
Public Health England
Directors for onward distribution to:
- Laboratory managers
Establishments registered with the Care Quality Commission (CQC) (England only)
- Hospitals in the independent sector
- Independent treatment centres
- Private medical practitioners
Send enquiries about this notice to MHRA, quoting reference number MDA/2016/008 or 2016/004/001/601/011
Salman Ghani, MHRA
Tel: 020 3080 6920
Mark Grumbridge, MHRA
Tel: 020 3080 7128
Reporting adverse incidents in England
Alerts in Northern Ireland are distributed via the NI SABS system.
Enquiries and adverse incident reports in Northern Ireland should be addressed to:
Northern Ireland Adverse Incident Centre, CMO Group,
Department of Health, Social Services and Public Safety
Tel: 028 9052 3868
Fax: 028 9052 3900
Please report directly to NIAIC using the forms on our website.
Enquiries and adverse incident reports in Scotland should be addressed to:
Incident Reporting and Investigation Centre,
Health Facilities Scotland,
NHS National Services Scotland
Tel: 0131 275 7575
Fax: 0131 314 0722
Reporting adverse incidents in Scotland
NHS Boards and Local Authorities in Scotland – report to Health Facilities Scotland.
Contractors such as private hospitals carrying out NHS work and private care homes that accept social work funded clients – report to Health Facilities Scotland.
Enquiries in Wales should be addressed to:
Healthcare Quality Division,
Tel: 02920 823 624 / 02920 825 510
Reporting adverse incidents in Wales
Published: 22 June 2016
Issued: 22 June 2016
Alert type: Medical device alert