Portable blood glucose meters

Portable blood glucose meters and strips which use the enzyme glucose dehydrogenase pyrroloquinoline quinone (GDH-PQQ) also known as glucose-dye-oxidoreductase have the potential to also detect the sugars galactose and xylose (monosaccharides) and maltose (disaccharide) and hence provide a false high glucose reading in the presence of these substances. 

There are also blood glucose meters and strips that use mutant variant GDH methods which are not subject to interference from maltose.

Two potential adverse clinical consequences can occur:

1. Patients with falsely elevated blood glucose readings may receive an excessive dose of insulin resulting in hypoglycaemia, or
2. Patients with low blood glucose (hypoglycaemia) may go untreated due to masking of their true blood glucose levels by falsely elevated results.

An article was published on the TGA website in 2005 as a result of reported adverse events. 

The TGA has continued to monitor the occurrence of this type of incident and noted that further adverse events have been reported in Australia and worldwide between 2005 and 2010. 

Although the overall rate of incidence occurrence has not markedly increased, an updated advisory is being issued as a precautionary measure.

A review of the portable blood glucose monitors on the Australian Register of Therapeutic Goods (ARTG) has identified the following devices which utilise the GDH-PQQ technology.

Company	Device name	ARTG#
Abbott Diabetes Care	Optium Omega test strips	141948
	Freestyle Lite blood glucose test strip - replaced with strips that use GDH-FAD chemistry in June 2010. Some strips with GDH-PQQ chemistry may still be in use however no stock using this chemistry is available through the normal channels of supply.	148264
Roche Diagnostics Australia	Accu-chek Mobile monitoring system - replaced with strips that use mutant quinoprotein glucose dehydrogenase (Mut. Q-GDH) in November 2010. Some strips with the GDH-PQQ chemistry may still be in use however no stock using this chemistry is available through the normal channels of supply. Test strips using Mut. Q-GDH can be identified by its packaging. The boxes are marked with a green box bearing black strips as seen here	166975
	Accu-chek Integra drum	107421
	Accu-chek Go glucose strip	99803
	Accu-chek Advantage sensor	170505
	Accu-chek Advantage II sensor	65308
	Accu-chek Active strip	79458

Drug substances or therapies with non-glucose sugars which can interfere with GDH-PQQ based blood glucose tests are listed below:

• Icodextrin e.g. the peritoneal dialysis solution Extraneal
• Some immunoglobulins e.g. Octagam 5%, Gamimune 5%
• Orencia
• Adept adhesion reduction solution (4% icodextrin)
• Some radioimmunotherapy agents e.g. BEXXAR
• Any product that contains or is broken down by the body into the sugars maltose, galactose or xylose

Patients undergoing treatment with any of the above substances must not use blood glucose monitors utilising GDH-PQQ technology.

Information for patients and healthcare professionals

1. Be familiar with the type of glucose monitoring technology you are using by either consulting the instructions for use, the sponsor of the device, your pharmacist or your doctor.
2. If you are on any therapy or drug listed above do not use meters or strips which use GDH-PQQ. Portable blood glucose test meters using other enzymes (GOD, GDH-NAD, GDH-FAD, Mut. Q-GDH) should be used.
3. GDH-PQQ based testing can be used if you are not undergoing treatment that will interfere with the result.
4. Blood glucose monitors utilising any form of GDH-PQQ technology must not be used on neonates with galactosaemia as galactose can still interfere with all forms of GDH-PQQ technology.