Lab Tests in Diabetes Flashcards
Why would lab tests be useful in diagnosis?
Confirmation or rejection of clinical diagnosis
Why would lab tests be useful in monitoring?
Monitor natural history or response to treatment
Why would lab tests be useful in prognosis?
Prediction of course or outcome of disease
Give another situation in which lab testing is useful
Screening - detection of sub-clinical disease
Name the 2 analytical factors
Accuracy
Precision
Describe the 2 analytical factors
Accuracy - can the method produce the correct result
Precision - can it do this consistently
What is the reference (‘normal’) range?
Mean +/- SD from sample of healthy population
Can results from healthy patients fall outside reference range?
Yes - approx 5%; important to look in clinical context
Name the 4 blood sample tests done in diagnosis of diabetes, and the expected results
Random venous plasma glucose > 11.1mmol/L
Fasting plasma glucose > 7mmol/L
2 hour plasma glucose > 11mmol/L
HbA1c >48mmol/mol
In what situation is 2 hour plasma glucose used?
OGTT is done in people with impaired fasting glucose
What is HbA1c useful in diagnosing?
Type 2 diabetes
Can blood glucose meters be used to diagnose diabetes?
NO; not precise enough, lab test is required
If the patient is asymptomatic, how should lab tests be done?
Requires confirmation by repeat testing on another day
In what patients should HbA1c not be used to diagnose diabetes in?
Children + young people Suspected type 1 Symptoms <2 months Acutely ill patients Patients on meds that cause rapid glucose rise (e.g. steroids) Acute pancreatic damage Pregnancy Patients w genetic, haematological or illness-related factors that affect HbA1c
Name 2 methods of point of care testing in diabetes
URINE TESTING (glycosuria, ketonuria) GLUCOSE METER (measurement of capillary blood glucose)
