Clinical biochemistry in diabetes Flashcards

1
Q

why are lab tests used

A

diagnosis
monitoring
prognosis
screening

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2
Q

what 2 characteristics do good tests have

A

accuracy - can the method produce the correct result

precision - can it do this repeatedly

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3
Q

why are lab tests used in diabetes

A

diagnosis

monitoring - acute, chronic

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4
Q

what lab tests can help diagnose diabetes

A

Random venous plasma glucose >11.1mmol/L

Fasting plasma glucose >7.0mmol/L

2 hour plasma glucose >11.1mmol/L in OGTT

HbA1c >48mmol/mol (Type 2 Diabetes only)

If asymptomatic, requires confirmation by repeat testing on another day

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5
Q

what is monitored in HbA1c

A

HbA1c - intracellular within RBCs

high blood glucose levels

  • glucose not taken into cells due to lack of insulin (absolute or relative)
  • glucose moves freely into RBCs
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6
Q

when would you not use HbA1c to aid diagnosis

A

Children and young people

Suspected Type 1 diabetes

Symptoms <2 months

High risk patients who are acutely ill

Patients taking medication that may cause rapid glucose rise (e.g. steroids)

Acute pancreatic damage

Pregnancy

Presence of genetic, haematological or illness-related factors that affect HbA1c and its measurement

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7
Q

what lab tests can aid in acute monitoring

A

urine testing (dipstix):
glycosuria
ketonuria

glucose meter:
measurement of capillary blood glucose

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8
Q

CASE: 21 year old student

  • thirst, polyuria and weight loss over the last two months; - became unwell with flu-like symptoms and began vomiting.

Urinalysis-
Glucose ++++
Ketones ++

Dehydrated, tachypnoeic and generalised abdominal tenderness, admitted to the surgical ward on 40% O2

diagnosis?

A

diabetic ketoacidosis

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9
Q

what is factitious hypoglycaemia

A

high insulin levels in absence of elevated C-peptide concentrations

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10
Q

what is insulinoma

A

elevated C-peptide level indicative of insulin-secreting tumour

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11
Q

what are some of the chronic complications of diabetes

A

macrovascualr disease

  • TIA, stroke
  • angina, MI, cardiac failure

microvascular disease

  • diabetic retinopathy
  • nephropathy
  • erectile dysfunction
  • foot problems
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12
Q

what lab tests are involved in chronic diabetes monitoring

A

Glucose (self-monitoring of blood glucose)

HbA1c (Glycaemic control)

Urine Albumin/creatinine ratio (Diabetic renal disease - Microvascular screening)

Lipids (Macrovascular screening)

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13
Q

what is ACR (albumin/creatinine ratio) used to screen for

A

diabetic kidney disease

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