POC devices for diabetes

Question 1

Can pharmacy technicians perform POC testing?

Answer 1

Yes,
pharmacist to interpret results

Question 2

What are steps to perform POC?

Answer 2

1. Purpose of POC
2. Get consent
3. Appropriate storage of devices
4. Clean and safe environment
5. Infection prevention procedures
6. Document in patient record
7. Notify primary care provider

Question 3

How do glucometers work nowadays?

Answer 3

1. Blood is drawn via capillary action
2. Enzyme oxidizes glucose to gluconolactone
   - either glucose oxidase or dehydrogenase
3. Electrons from glucose transferred to oxidized mediator molecule (mediator becomes reduced)
4. Mediator delivers electrons to an electrode
5. Electrode quantifies NUMBER of electrons
   –> BG reading

Question 4

What are cofactors responsible for in the glucometers?
What are the 3 options for co-factors?

Answer 4

Co-factors:
- transport of electrons from glucose to the mediator

PQQ (pyrrolo-quinoline quinone)
FAD (flavin adenine dinucleotide)
NAD (nicotinamide adenine dinucleotide)

Question 5

How ACCURATE do glucometer readings have to be if reading UNDER 5.6mmol/L? OVER 5.6mmol/L?

Answer 5

UNDER 5.6mmol/L?
- 95% must be within +/- 0.8mmol/L

OVER 5.6mmol/L?
- 95% must be within +/- 15%

Question 6

How PRECISE do glucometer readings have to be if reading UNDER 5.6mmol/L? OVER 5.6mmol/L?

Answer 6

UNDER 5.6mmol/L
- SD less than 0.3mmol/L

OVER 5.6mmol/L
- Coefficient of variance (CV) <5%
CV= SD/mean

Question 7

What can cause falsely HIGH readings in glucometers?
THAABU

Answer 7

Triglycerides >5000mg/dL
Hematocrit <20%
Acetaminophen >8mg/dL
Ascorbic acid
Bilirubin >20mg/dL
Uric acid >10-16 mg/dL

Question 8

What can cause falsely LOW readings in glucometers?

Answer 8

• Hematocirt >55%

Question 9

What is the MOA of falsely high readings?

Answer 9

Acetaminophen , uric acid, ascorbic acid, bilirubin are oxidized instead of mediator (ferrocynaide),
- increases electrons –> higher BG reading

Question 10

How to test for peritoneal dialysis patients? What is the issue?

Answer 10

Some glucometers read maltose as glucose
- causes high BG readings

Question 11

What test is used for glucose in urine?

Answer 11

Diastix

Question 12

How do Diastix work?

Answer 12

1. Patient urinates directly on strip
2. Glucose is oxidized by glucose oxidase to form - Gluconic acid + hydrogen peroxide
3. Hydrogen peroxide oxidizes potassium iodide to form an iodine complex –> coloured product
4. Color is compared to chart

Question 13

What interferes with Diastix (glucose in urine) (3)

Answer 13

1. Ascorbic acid
2. Urine with high specific gravity
3. Ketone bodies

Question 14

What are disadvantages of glucose in urine tests? (5)

Answer 14

• Inability to detect hypoglycemia
• Many possible drug interferences (SGLT2)
• Lack of correlation with BG levels
• Difficulty in reading tests
• More privacy required

Question 15

How does continuous glucose monitoring test for glucose?

Answer 15

Sensor inserted under skin that measures interstitial glucose
- sends readings to monitor

Question 16

Advantages of continuous glucose monitoring tests

Answer 16

• Alarms when glucose levels are too low/high
• tracks glucose trends too

Question 17

disadvantages of continuous glucose monitoring tests

Answer 17

Sensor must be replaced every few days
levels may “lag” with interstitial measurement vs blood measurement

Question 18

How do flash glucose monitoring test glucose? Advantages

Answer 18

Same as continuous glucose monitoring (interstitial glucose)
- may not require calibration
- no alarms

Question 19

What are the benefits of POC A1C testing vs lab testing (4)

Answer 19

• results obtained during patient visits
• NO DELAYS in adjusting treatment regimens
• Save the patient a trip to the lab
• Accurate readings

Question 20

What can interfere with A1C measurements?

Answer 20

• Hemoglobinopathies
• Anemias ex. sick cell anemia
• Antioxidant supplementation ex. vit E, C
• Elevated bilirubin, triglycerides
  Drugs
• ASA
• Caffeine
• Acetaminophen
• Hydroxyzine

Question 21

When are ketone bodies present in elevated glcuose?

Answer 21

During fasting
Prolonged exercise
High-fat diet
when insulin is lacking

Question 22

When should ketone urine testing for diabetes be tested? (4)

Answer 22

• Acute stress/illness
• Consistently elevated BG readings
• During pregnancy
• Symptoms of DKA: Nausea, vomiting, abdo pain

Question 23

What do ketones measure?

Answer 23

Acetoacetic acid

Question 24

What is the reaction for ketone tests?

Answer 24

Acetoacetic acid reactions with nitroprusside to produce a coloured (lavender) substance
- compare colour to reference chart

Question 25

What are reasons for false positives of urine ketone tests? (2)

Answer 25

• drugs with sulfhydrol groups such as captopril, n-acetylcysteine
• Acetoacetic acid still present in urine after blood levels normalize

Question 26

What are reasons for false negatives of urine ketone tests? (1)

Answer 26

Ascorbic acid - vit C

Question 27

What do ketones in capillary blood tests measure?

Answer 27

B-hydroxybutyrate

Question 28

What do the at home cholesterol measuring devices measure?

Answer 28

Total cholesterol

Question 29

What are the professional use cholesterol devices called?

Answer 29

Cholestech, cardio check

Question 30

How do the professional cholesterol devices work?

Answer 30

Use enzymatic reactions to produce coloured substances and photometric detection

Question 31

What do Cholestech LDX measure?

Answer 31

• Total cholesterol
• HDL-C
• triglycerides
• LDL-C
• glucose
• alanine aminotransferase

Question 32

What do Cardiocheck PA measure?

Answer 32

• Total cholesterol
• HDL-C
• triglycerides
• LDL-C

other strips available that can measure glucose and ketone

Question 33

What are the interfering substances for cholesterol-measuring devices

Answer 33

Many interfere
interference is less than 10%