Diabetics could be giving up vital home blood sugar checks because they believe they are of no use, says a researcher.
Blood monitoring can spot when sugar levels are too high
Psychologist Dr Elizabeth Peel interviewed type 2 diabetes patients, and found that many were confused over what to do with the results.
Writing in the British Medical Journal, she said that some doctors simply ignored detailed records kept by diabetics, compounding the problem.
Charity Diabetes UK called for more support for patients.
In type 2 diabetes, levels of glucose in the blood can get too high, which in the long term can be damaging to health.
Home blood glucose testing devices, which work by analysing a pinprick of blood, can be bought at many high street chemists.
They allow patients to monitor the peaks in their blood sugar levels, in theory to help them adjust their diet to keep levels stable, and to seek medical advice if they are consistently too high.
Dr Peel, from Aston University, carried out detailed interviews with 18 patients over a four-year period to find out whether they were complying with this testing regime, and what they thought about it.
She found that while some found it reassuring, others were coming to the conclusion that it was pointless.
One patient told her: "Well I'm filling out this book, nobody ever looks at it - and you go to the doctors, and they take your blood, and they can decide from what your levels are - so why am I inflicting this pain on myself for nothing?"
Others started out testing regularly, then ended up testing less and less often, and there was some confusion over the right point to go back to the GP, even among those who said that their blood glucose levels were high.
Dr Peel urged health professionals to be explicit about whether and when such patients should self monitor and how they should interpret and act upon the results, especially high readings.
She said: "The role of health professionals is crucial, particularly as patients seem to need more guidance about interpreting and responding to readings.
"If patients cannot understand their blood glucose fluctuations they cannot modify their behaviour."
Some experts believe that daily self monitoring helps to control blood glucose levels and it is often recommended.
But others believe that self monitoring is complex and inconvenient and can lead to feelings of frustration and guilt.
As such, there is still no firm agreement about the role and value of self monitoring for patients with type 2 diabetes.
A spokesman from Diabetes UK said: "Unfortunately, we are aware that many people with diabetes, in particular those with type 2, are not been given adequate education to enable them to manage their diabetes for themselves by acting on the meter readings effectively.
"We would support healthcare professionals in providing information and resources to make sure that people with diabetes can make the appropriate choices when it comes to self-monitoring."