Diabetes Testing

Question 1

What tests your plasma glucose?

3

Answer 1

1. Fasting plasma glucose (FPG)
2. Random plasma glucose (RPG)
3. Two-hour plasma glucose during an oral glucose tolerance test (2-h OGTT)

Question 2

What is the normal FPG?

Increased risk for Diabetes “Pre-diabetes”:
Impaired fasting glucose?
Impaired glucose tolerance?

Diabetes Mellitus:
Hem A1C ?
FPG ?
2h OGTT ?
Symptomatic hyperglycemia RPG ?

Answer 2

Normal: FPG is less than 100mg/dL

Impaired fasting glucose (IFG): 100-125
Impaired glucose tolerance (IGT): 2h OGTT of 140-199

Diabetes Mellitus:
Hem A1C ≥ 6.5%
FPG ≥ 126
2h OGTT ≥ 200
Symptomatic hyperglycemia RPG ≥ 200

**Critical Note: Diagnosis must be confirmed on a subsequent day by measuring any one of the criteria

Question 3

What is the sensitivity and specificity of the 126 level if using the 2h OGTT ≥ 200 as the reference standard?

Answer 3

Specificity > 95 percent (the ability to rule it in)
Sensitivity about 50% (the ability to rule it out)

In other words, a person that has an FPG of 126 or higher highly likely has diabetes, but a person with a level of, let’s say 120, may still have diabetes when using the 2h OGTT criteria as a reference

Question 4

Factors that affect blood sugar?

3

Answer 4

Medications

Emotional stress

Physical stress

Question 5

_____released during stress increase blood sugar.

What kind of stress? 5

Answer 5

Hormones

Physical or emotional stress

1. Surgery
2. Infection
3. Stroke
4. MI
5. Emotional stress and anxiety

Question 6

What can elevate blood sugar other than diabetes, IFG, or IGT?
8

Answer 6

1. Medications
2. Stress hyperglycemia
3. Cushing’s syndrome,
4. acromegaly,
5. pheochromocytoma,
6. glucagonoma,
7. liver disease,
8. pancreatitis

Question 7

What meds can elevate blood sugar?

4

Answer 7

Steroids
Beta-blockers
Nicotinic acid
Estrogens

Question 8

Recommendations For Diabetes Screening?

3

Answer 8

1. FPG screening every 3 years beginning at age 45 years
2. Consider screening at an earlier age (or more frequently if >45yo) if diabetes risk factors are present
3. BMI ≥ 25 + 1 or more risk factors

Question 9

What are the screening tests?

If tests are normal then when should you retest?

Answer 9

1. A1C,
2. fasting plasma glucose,
3. 2 h oral glucose tolerance test

If the tests are normal do it again in three years

Question 10

DM Risk factors - review

14

Answer 10

1. Age ≥ 45
2. BMI ≥ 25
3. FmHx of DM in a 1st degree relative
4. Hx of gestational DM
5. High risk ethnicity (African 6. American, Hispanic, Native American, Asian American, Pacific Islanders)
6. Hypertension
7. HDL less than 35
8. Triglycerides ≥ 250
9. A1C ≥ 5.7
10. Polycystic ovarian syndrome
11. Vascular disease
12. Sedentary lifestyle
13. IFG/IGT

Question 11

For the diagnosis of diabetes ______ are necessary.

What is not recommended? 2

Answer 11

plasma samples

1. Point of care testing for A1C is not recommended for diagnosis
2. Finger stick blood glucose is not used for diagnosis

Question 12

Why do we not use fingerstick for diagnosis?

2

Answer 12

1. Venous glucose levels may be higher than capillary levels
   For fasting samples and random testing (FPG)
2. Venous glucose levels lower than capillary
   2 h after oral glucose load

Question 13

AT what levels for FPG do we diagnose as DM?

ANything lower than this value we treat as what?

Answer 13

126 or over.
Anything lower than that and we treat it as impaired fasting glucose
(need two tests)

Question 14

At what level for random glucose testing do we diagnose diabetes?

What do we follow it up with before we determine the diagnosis?

Answer 14

over 200

FPG

(If the RPG is 200 but FPG is less than 126 then we still treat as IFG)

Question 15

The _______ is a way to measure the mean glucose level over 3 months. How does it do this? 3

Answer 15

hemoglobin A1C

1. Hemoglobin that is formed in new red blood cells enters the circulation without any glucose attached
2. Red cells are freely permeable to glucose
3. Glucose becomes irreversibly attached to hemoglobin at a rate dependent upon the prevailing blood glucose

(What percent of your red blood cells are coated in sugar)

Question 16

Hemoglobin A1C correlates best with mean blood glucose over what period of time?

Answer 16

Correlates best with mean blood glucose over the previous 8 to 12 weeks.

Question 17

Hemoglobin A1C
sources of error?
2

Answer 17

1. red blood cell turnover is low (delayed) = flasely high A1Cs
2. rapid red cell turnover leads to a greater proportion of younger red cells and falsely low A1C values.

Question 18

Factors that may alter A1C results:
Increase? 6
Decrease? 4

Answer 18

Increase:

1. Iron deficiency anemia
2. Alcohol toxicity
3. Lead toxicity
4. Late pregnancy due to the iron deficiency anemia
5. Genetic variants
6. Hgb S, Hgb C traits

Decrease:

1. Hemolytic anemia
2. Chronic blood loss
3. Pregnancy
4. Chronic renal failure

Question 19

Routine hemoglobin A1C testing?

2

Answer 19

1. At least twice yearly if meeting DM treatment goals

2. Test q 3months if previous medication change or not meeting treatment goals

Question 20

Fructosamine shows the average of blood glucose control over what period of time?

Answer 20

1-2 weeks of average blood glucose control

Question 21

Why would you measure Fructosamine?

3

Answer 21

1. Pregnant
2. Blood loss/hemolytic anemia
3. sickle cell

(in these pts the hemoglobin A1C will be falsely high or low)

Question 22

Abnormal levels of what would cause irregularities in fructosamine?

You would see falsely low levels of it with what?

Answer 22

Albumin

Falsely low levels with rapid albumin turnover

Question 23

What are we looking for in the urine?

3

Answer 23

Glucose

Ketones

Protein

Question 24

Glucose in blood is normally filtered at the glomerulus with almost complete reabsorption taking place where?

Answer 24

taking place in the proximal tubule

Question 25

Glucose in the urine signifies what? At what levels does glucose in the urine usually occur?

Answer 25

that the filtered load is exceeding the absorptive capability of the proximal tubule over 180

Question 26

27

Answer 26

27`

Question 27

What does glucosuria lead to? What should we do if this occurs?

Answer 27

Osmotic diuresis Check a blood sugar

Question 28

Where are ketones produced? They are part of what kind of metabolism? Why do ketone levels increase? Is it more common in type 1 or 2 and why?

Answer 28

Produced in the liver Part of fatty acid metabolism Increase when not enough insulin to use glucose for energy It occurs when the body cannot use sugar (glucose) as a fuel source because there is no insulin or not enough insulin. (no insulin in type one)

Question 29

What are the three types of ketones? Why does positive test for ketones mean excessive amounts??

Answer 29

1. Beta-hydroxybutrate (in DKA most are in this form) 2. Acetoacetate 3. Acetic Acid There are normally small amounts of ketones present in the serum and urine (which are not detected by conventional testing) --so you get a positive there has to be a lot!!!!!

Question 30

In the patient with DKA, urine may be negative for ketones if _____ exists? The test reacts strongly to what kind of ketone and not strongly with which ketone?

Answer 30

if severe renal insufficiency (kidneys may be unable to filter ketones) Test reacts strongly to acetoacetic acid but not with beta-hydroxybutyrate. In DKA, most of the ketones present are in the form of beta-hydroxybutyrate **Negative or weakly positive urine ketone should not sway clinician from possibility of ketoacidosis if presentation is suggestive

Question 31

Where else might you see ketoacidosis? | 3

Answer 31

starvation vomitting low carb diets

Question 32

When to test ketones? | 3

Answer 32

Pregnancy Elevated blood sugars > 300 When suspicious for DKA

Question 33

Ketones will be detectable in the urine with the following? | 8

Answer 33

1. Poorly controlled DM 2. DKA 3. Starvation 4. Strict Atkins* diet 5. Poisoning 6. Certain types of anesthesia 7. Alkalosis 8. Some metabolic disorders

Question 34

Ketonuria: False positive tests | 4

Answer 34

Levodopa Phenazopyrine Valproic acid Vit C

Question 35

Albuminuria: To show up on a regular urine dipstick as + for protein, levels need to be where?

Answer 35

≥300 mg

Question 36

Screening for albuminuria | 3 times

Answer 36

5 years after the diagnosis of Type 1 Upon diagnosis of Type 2 Then annually for all diabetics

Question 37

Albumin to Creatinine Ratio (ACR) correlates well with what kind of sample? At what levels do you have microalbumemia?

Answer 37

Correlates well with a 24h urine sample Microalbuminuria = 30-300 mg albumin/g of creatinine

Question 38

Diagnosis of diabetic nephropathy? | 2

Answer 38

Confirm a positive result with additional tests over the next 3-6 months 2 out of 3 samples that are abnormal within a 6 month period = diabetic nephropathy

Question 39

Why should patients self monitor their glucose? | 3

Answer 39

1. To maintain good glucose control 2. Allows adjustments of insulin and diet content to be made based on immediate feedback of glucose results 3. Allows timely intervention for low glucose readings to avert serious hypoglycemic events

Question 40

Self monitoring blood glucose: When should patients test? 5

Answer 40

Frequency of testing depends on may factors 1. Fasting AM 2. Before and after meals 3. Before, during and after exercise 4. Before bedtime 5. Periodically 2-3 AM?

Question 41

Self monitoring blood glucose. How often should it be done: Type 1? Type 2?

Answer 41

Type I DM – at least three times daily | Type II DM – depends on degree of control and what medications the person is taking

Question 42

With decreasing or increasing blood sugars is there less accuracy?

Answer 42

With decreasing blood sugars there is less accuracy

Question 43

Continuous Glucose Monitoring | measures interstitial fluid how? 2

Answer 43

Measures interstitial fluid by: 1. Needle sensor inserted subq 2. Whole device implanted subq

Question 44

In general what does continuous glucose monitoring help with?

Answer 44

hypoglycemia episodes

Question 45

What are the numbers for impaired fasting glucose? What are the numbers for impaired glucose tolerance? What is the fasting blood sugar needed for diagnosis of diabetes? What A1C level diagnoses diabetes and what are the numbers for treatment goals?

Answer 45

100-125 140-199 126 or higher on two sepeatrate occsions 6.5 or higher on two separate occasiosn. 10% or less

Question 46

If you get an abnormal plasma glucose or A1C what now? What random blood glucose constitutes diabetes? What are some commonly used medications that affect serum glucose? 4

Answer 46

Get a FPG greater than 200 with symptoms 1. steriods, 2. beta blocker, 3. nicatinic acid and 4. estrogens.