monitoring control in diabetes Flashcards
at what points do you assess diabetic/glycaemic control
diagnosing diabetes, day to day, initating/altering treatment, evaluate long term control, in emergency diabetic ketone acidosis, hyperglycemia
what are the biochemical investigation available to do with diabetes control
hba1c, random glucose test, fasting glucose test, urine glucose,Oral Glucose Tolerance Test (OGTT), albumin creatinine ratio, ketones
what is the goal of blood glucose monitoring
maintain glucose within target range
what are some immediate benefits of monitoring blood glucose
identify highs and lows and prevent and treat them, also some people are unaware when they are hypo
what are the long term benefits of monitoring blood glucose
prevent long term complications e.g cvd and macrovascular and microvascular
what is a POCT
test at the point of care, (glucometers to measure blood glucose),
what are the pros of doing poct
life threatening conditions can be stabilized more quickly, immediate risk stratification, smaller sample volume, better patient compliance, reduce repeat clinical visits, less time in hospital and better disease control. accuracy of them is generally acceptable
what is turnaround time TAT
time taken for test result to come back and treatment initiated, poct significantly quicker as traditional methods the sample has to go back to the lab, be organised and sent back to the patient care unit.
what are the cons of poct
the person doing the poct may be incomptetent, equipment may not be maintained well, cost is usually greater than in the lab,
analytical info can be poorer than lab, and needs lab to back it u, poor patient info
how does capillary glucose testing work
prick finger with lancet, apply blood to reagent strip, record results.
POCT represents glucose in what compartment of the blood
PLASMA
why does plasma have more glucose dissolved in it than blood
because it has a higher water content so more glucose dissolves there, becomes significant when centrifuging
why does glucose concentration in blood fall by 0.5mmol over 3 hours
because of glycolysis in rbc, it can be inhibited with fluoride oxalate to improve accuracy of test
a woman who is pregnant has glucose in her blood should I be concerned?
no small amounts of glucose in pregnant women is normal however consistent glycosuria can indicate gestational diabetes
what are the disadvantages of urine glucose
it is retrospective, cannot be used to diagnose diabetes, fluid intake affects urine conc, renal threshold can differ
if you want to look at long term blood glucose control what entities do we look at
glycated haemoglobin(1-3 months) and serum fructosamine (2weeks)
Advantages of HbA1c for diagnosis
patients don’t have to fast, acute stress does not effect test, small biological variation, better index of overall glycaemia, stable in vitro
disadvantages of HbA1c for diagnosis
cost, misleading in patients with shorter lifespan for rbc, renal failure and anaemia, increases with age, ethnicity, glycation rate differs between individuals
Situations where HbA1c must not be used
in symptomatic children and young people, symptoms that suggest type 1 diabetes,
patients with meds causing rapid glucose rise, pancreatic issues, also hba1c will not detect acute rapidly raised glucose levels
what can intefere with hba1c measurement
variants to hb, hbf elevated in diabetes can elevate and hbs and hbc can lower,
altered red blood cell survival, vitamin c can lower, and drugs can modify hb effecting hba1c
how do you measure hba1c
boronate affinity chromatography, run blood over , glycated hb binds and non hb elutes at first peak.
glycated hb elutes as second peak
what is fructosamine
Fructosamine is essentially glycated albumin
why is fructosamine analysis for glucose control more useful than hba1c in a pregnant woman
Measure of long-term control over lifetime of
serum albumin – about 2 weeks (useful when
control changing quickly e.g. pregnancy)
how do you measure fructosamine
Usually measured with colourimetric assay
Reference range ~200-285 mmol/l
The future of blood glucose monitoring
Ideal glucose monitoring device
Minimally invasive or non-invasive
Continuous sensing
what is continous glucose montoring (cgm)
Measures glucose in the tissue Lags behind blood glucose (5-15 min) Provides “real time” glucose readings Glucose concentration Direction / rate of change Alarms to warn of high or low blood sugars
what are pros of cgm
Frequency of testing = more data to work with
Viewing of trends allowing easier predictions and fine tuning of
treatment
Less frequent need for finger sticks
Less likelihood of complications because of uncontrolled
diabetes
Helps detect hypoglycaemic unawareness
what does post prandial mean
after eating a meal
what are cons of cgm
implanted sensor is not designed for long term use, efficiency and accuracy, cost
