Ketones

What are Ketones?

Cells require a constant supply of energy to allow normal metabolic turnover and cell function. Glucose serves as a major source of this energy. When glucose is unavailable, other energy sources, including fats, can be utilised. Ketone bodies are produced as a by-product of fat metabolism and are used to supply energy to the brain. The presence of excess ketones in the blood and urine is a useful indicator of glucose unavailability.

Starvation, lack of glucose intake, or increased glucose consumption during stress or exercise, for example, may all increase ketone production. The presence of excess ketones is also common in undiagnosed or poorly controlled type 1 diabetics, as lack of insulin production prevents glucose uptake into cells and therefore prevents glucose metabolism.

The presence of ketone bodies in these patients is often accompanied by elevated blood glucose levels and abnormal blood pH. This condition is referred to as diabetic ketoacidosis. Ketosis (elevated ketone bodies) or ketoacidosis (elevated ketone bodies with the presence of disturbances to pH), may be suspected in patients with elevated blood glucose levels, a fruity scent on the breath, confusion, excessive thirst and urination, deep or fast breathing, nausea and abdominal pain.

Excess ketones may be detected in both the blood and the urine, as excess ketones are filtered through the kidney to pass into the urine.

So how can you be confident that your device is giving the right result every time it's used?

How can you be sure that your device continues to work as the manufacturer originally intended?

There are 3 key steps that you can take to assure the quality of your results:

Know what you are doing
  • Healthcare Professionals should always be trained by the device manufacturer or local laboratory staff and be certified as competent to perform the test.
  • Make sure you have read and understood the instructions supplied with your testing device.
  • Pay attention to any limitations that may be listed – this means that the device may not be suitable for:
    • Patients with certain disease conditions
    • Patients taking certain medications
    • Certain types of sample e.g. random urine vs early morning urine
    • Certain types of sample collections tubes (e.g. added preservatives)
  • Make sure your consumables and quality control solution (if used) have not passed their opened or unopened expiry dates.
  • Make sure you are storing your test strips and QC solution at the right temperature.
    • Storing the test strips at the wrong temperatures can lead to inaccurate results.
  • Ensure any required routine maintenance is carried out (e.g. cleaning)
Use Quality Control
  • The manufacturer of your device may provide small bottles of Quality Control (QC) solution or you may be able to purchase them independently. You can analyse these solutions as if they were a patient sample and the documentation accompanying solution will state what result you should obtain.
  • The result you obtain for this QC solution should fall within the range/criteria of results quoted by the manufacturer.
  • When you run a QC test, you will know instantly whether the result is acceptable or not. Achieving good QC results will give you immediate information and the confidence to continue to use your device and act upon the results.
  • If your QC results are not within range, follow the manufacturer's instructions to troubleshoot this problem – do not continue to use the device for patient testing.
Use Qpoint External Quality Assessment
  • Participation in an External Quality Assessment Scheme or "EQAS" such as Qpoint for your device is recommended by the Medicines & Healthcare Regulatory Agency (MHRA) in the UK1.
  • When you enrol and participate in Qpoint, you are sent a monthly sample of urine to test on your device. You do not know what the correct result should be.
  • You then submit your result to Qpoint, who compare your result to the results that other users of the same device have submitted for the same test sample.
  • There may be many of users of the same type of device registered with the scheme from around the UK, or internationally, that your result will be compared to.
  • The following month, when you receive your next test sample, you will also receive a report that tells you how well your previous result agreed with all other users of the same device registered with our scheme.
  • The Qpoint report is easy to understand and gives advice on any action that you may need to take to improve the quality of your results.
  • If your EQA test results are in good agreement with other users of the same device you will have reassurance that your device and consumables are working as they should under your own local conditions. It also gives you confidence that your testing procedures continue to meet the manufacturer's specification.
  • The Qpoint organisers work independently of device manufacturers, but when problems are identified with any particular instrument, the manufacturer is advised and encouraged to address the issue.
  • Any serious problems identified are reported to the MHRA.

1 MHRA Device Bulletin: Management and Use of IVD Point of Care Test Devices. DB2010 (02) February 2010

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