SESSION 05

Blood glucose: The main sugar found in the blood, and is the body’s main source of energy.

Blood glucose estimation is performed to determine the concentration of sugar in the blood.

When it is above normal it is called hyperglycaemia and when it is below normal is called hypoglycaemia.

This test is useful in diagnosing diabetic suspected patients.

Diabetic patients have high level of glucose in blood.

Blood glucose estimated at any time of the day even when the patient taken a meal is called random blood glucose.

Usually these values show slight elevation and are therefore less reliable as an indicator of diabetes.

Therefore, in order to confirm high glucose levels in the blood, a fasting blood sugar estimation test must be requested before taking meals.

TYPES OF SPECIMENS FOR BLOOD GLUCOSE ESTIMATION

Fasting blood specimen: Blood collected after 10 – 16 hours before taking meals in adults and six hours for children

Post prandial specimen: Blood collected two hours post prandial (after food intake)

Random specimen: Blood sample collected at any time, regardless of food intake.

Purpose

This test measures blood glucose levels at any time of the day, regardless of when the person last ate. It is used to assess current glucose levels and to screen for diabetes or evaluate glucose control in people with diabetes.

Procedure: – A blood sample is taken at any time without regard to the timing of meals. It can be done at home using a glucometer or at a healthcare facility.

Interpretation: – Normal random blood glucose levels typically range between 70 to 125 mg/dL (3.9 to 6.9 mmol/L) in adults. Levels above this range may indicate hyperglycemia, while levels below may indicate hypoglycemia.

Purpose

This test measures blood glucose levels after an overnight fast (usually 8 to 12 hours). It is commonly used to diagnose diabetes, assess glucose control in people with diabetes, and screen for prediabetes.

Procedure: The person abstains from eating or drinking (except water) overnight before having their blood drawn in the morning. The blood sample is then analyzed for glucose levels.

Interpretation

Normal fasting blood glucose levels typically range between 70 to 100 mg/dL (3.9 to 5.6 mmol/L) in adults. Levels between 100 to 125 mg/dL (5.6 to 6.9 mmol/L) may indicate prediabetes, while levels of 126 mg/dL (7.0 mmol/L) or higher on two separate occasions may indicate diabetes.

Type of sample is whole blood from capillary blood or venous blood.

Materials need for blood collection

Glucometer; a portable device used to measure blood glucose level. Consist meter, test strips and lancet device.

Test strips

Control solution

Calibration solution

Battery

Glucose estimation should be done immediately after blood sample collection.

if there is any delay in the blood sample, the test is collected in the bottle containing fluoride anticoagulant.

NB: MOA its means mode of action.

Blood glucose testing can be used to screen healthy, asymptomatic individuals for diabetes and pre-diabetes, because diabetes is a common disease that begins with few symptoms.

Screening for glucose may occur during public health fairs or as part of workplace, health programs.

It may also be ordered when a patient has a routine physical exam

Screening is especially important for people at high risk of developing diabetes, such as

Those with a family history of diabetes,

Those who are overweight, and

Those who are more than 40 to 45 years old.

SYMPTOMS OF HYPERGLYCAEMIA

Increased thirst

Increased urination

Fatigue

Blurred vision

Slow wound healing

Sweating

Hunger

Trembling

Anxiety

Confusion

Blurred Vision

Glucometer by using blood sample such as Glucoplus or accucheck

Urine strips by using urine sample.

The meters are and small battery operated.

Require small volumes of blood.

Provide blood glucose results within 30 – 60 seconds.

Blood glucose is measured electrochemically.

Test results can be affected when

The amount of blood is either insufficient or too much

When blood is lipaemic

PROCEDURE

Insert a strip in the meter (turns on the meter)

Apply blood to the side of the strip (follow manufacturer’s instructions for the volume of blood)

Result is digitally displayed after a few seconds depending on the type of glucose meter

Adults

Fasting 3.6 – 6.4 mmol/L

Random 3.3. – 7.4 mmol/L

Children

Fasting 2.4 – 5.3 mmol/L

Newborn 1.1 – 4.4 mmol/L

FALSE RESULTS CAN BE DUE TO

A falsely high glucose level may be obtained when blood sample is collected from an arm receiving dextrose intravenous (i.v.) infusion.

A falsely low value may be obtained

If the blood sample is markedly icteric (patient with jaundice).

If the blood sample is collected in a tube with no fluoride anticoagulant as a result glycolysis will reduce actual number of glucose in a particular sample.