One Liners issue 54 - December 2007

Pulp Fiction!! Some general waste containers made of pulp material may leach substances such as nitrite into the collected urine specimen. These substances could interfere with urine dipsticks and lead to false results.

• Always choose a specimen collection device suitable for use for with urine dipsticks

Don’t get hooked Some users of chemistry or haematology analytical systems have observed false results due to hook effects (ie results appear negative when the sample is highly positive).

• Check with the manufacturer’s instructions for potential hook effects and implement recommended dilution protocols if required.

Alarm Bells! Unaware a Microbiology analyser computer had stopped communicating with the LIS system, the system failed to detect a positive sample. The audible alarm option on the analyser had been switched off.

• To reduce the risk of missing positive results, consider the use of audible alarms option on the analyser.

What a carry on When running two different tests on the same analyser, some users have observed false results due to carryover from one test interfering with the results of the second test.

• Always ensure that you are aware of known interferences and have implemented the manufacturers recommended precautions and actions to avoid carry over.

Is this PC? MHRA have received reports of problems with data transfer to laboratory information systems (LIS) resulting in incomplete records or incorrect identification.

• Ensure that the LIS you use is fully compatible with the medical devices linked to it.

It’s too darn hot! MHRA have received reports of incorrect results that turn out to be caused by reagents or samples kept in incorrect storage conditions.

• Always ensure that you are aware of the correct storage conditions for reagents and samples to be tested.

The One Liners editions are published by MHRA, an Executive Agency of the Department of Health.
If you would like to discuss or report an adverse incident, including "near-misses" involving a device, either contact your Trust Medical Devices Liaison Officer or contact us directly on 020 7084 3080. To discuss laboratory related issues, please call us on 020 7084 3271 which will go to a member of the IVD team.
You can find detailed reporting guidance on our website www.mhra.gov.uk