Blood + urine testing

Question 1

What are glucagon functions?

Answer 1

Gluconeogenesis 
Lipogenesis 
Ketogenesis 
Inhibit glycolysis 
Glycogenolysis

Question 2

After eating there is a rise in BGC what should this concentration not exceed?

Answer 2

Renal threshold

In diabetes glucose concentration exceeds renal threshold and more is excreted into the urine

Question 3

Describe how a glucometer works?

Answer 3

Glucose oxidase enzyme breaks down Glucose + O2 -> gluconolactone

H202 also produced which releases atomic oxygen + water

Atomic oxygen detected by electrode and signal sent to meter

Amount of atomic oxygen is proportionate to glucose conc. of the blood

Question 4

How can we measure blood glucose?

Answer 4

Oral glucose tolerance test

Glucometer

Question 5

Why is plasma glucose 10-15% higher than blood glucose?

Answer 5

Plasma has a higher water content than the whole blood, so there is more dissolved glucose in the plasma compared to the blood

Question 6

What effect do patients with type 2 diabetes lose?

What tests are done to diagnose this?

Answer 6

Oral glucose tolerance test
Incretin effect
Oral glucose causes greater insulin release compared to iV glucose

Question 7

How does the oral glucose tolerance test detect type 1 diabetes?

Answer 7

Patients eat sugary food source
Plasma glucose rises higher and is sustained for a longer time period due to the lack of insulin ( induces anabolism)

Plasma glucose > 11.1 mmol/L 2 hours post meal - T1D

Question 8

What can affect glucose concentration?

Answer 8

Diabetes 
Pregnancy 
Menstrual cycle 
Obesity 
Alcohol + dehydration
Stress 
Medications 
Food + activity 
Infection 
Fatigue

Question 9

What is a normal urine analysis?

Answer 9

• Absence of glucose, ketones, red blood cells, haemoglobin, myoglobin, protein, nitrites
• Negative leukocyte esterase test
• Specific gravity = 1.02 - 1.035 mOsm/Kg
• pH 4.5-8

Question 10

What is glycosuria?

What can cause it?

Answer 10

Presence of glucose in the urine

CKD, diabetes mellutis + some diabetic medications e.g SGLT2

Question 11

How are ketones produced?

When may they be present in the urine?

Answer 11

Fatty acid breakdown -> ketones
May be high in diabetic ketoacidosis : Glucose high blood but absence of insulin means that it cannot be taken up by cells and used as an energy source, ketones are produced to fuel cells + organs

Starvation ( ketones produced in fasted state)

Question 12

What is specific gravity?

Answer 12

This measure indicates the amount of solute dissolved in the urine and should be around 1.02-1.035 mOsm/kg in normal healthy individuals

Question 13

What may blood in the urine indicate ( RBC, Haemoglobin + myoglobin) ?

Answer 13

• UTI
• Urinary tract injury
• Renal stone
• Nephrotic syndrome
• Myoglobinuria
• Urinary tract malignancies

Question 14

What is a normal urine pH?
What may cause a low pH?
What may cause a high pH?

Answer 14

4.5-8
Low: Diabetic ketoacidosis, starvation, sepsis
High: Conditions affecting metabolic akalosis e.g vomiting, UTI, diuretics

Question 15

What can nitrites in the urine indicate?

Answer 15

UTI

Gram negative organisms such as E coli produce nitrites

Question 16

What can cause a positive leukocyte esterase result?

Answer 16

• Enzyme produced by netutrophils -> positive test signals WBC in urine
• Caused by UTI/ Haematuria

Question 17

How do we use plasma in the oral glucose tolerance test?

Answer 17

Patients fast overnight + fed 1g glucose/Kg

Blood samples taken every 3- minutes for 2 hours

Cells spun and plasma treated with perchloric acid

Glucose -> gluconic b. H2O2 also produced

H2O2 reacts with ABTS substrate in the presence of the perioxidase enzyme

Colour change shows

Colour of sample is compared to indicate amount of glucose in the sample