Glucose - Fasting Blood

Glucose - Fasting Blood

Overview of Glucose - Fasting Blood

What is Glucose - Fasting Blood?

The Fasting Blood Glucose Test is performed to measure glucose levels in the blood after a period of fasting to screen for and diagnose Prediabetes and Diabetes Types 1 and 2.

Sample Type

The sample type collected for Glucose - Fasting Blood is: Blood

Preparation for Glucose - Fasting Blood

  • Do not eat or drink anything other than water for 8-12 hours before the test.

Why Get Tested for Glucose - Fasting Blood?

The Fasting Blood Glucose Test is performed to:

·         Detect Diabetes mellitus

·         Screen for high blood sugar in presence of risk factors of Diabetes

·         Detect diabetes during pregnancy or gestational diabetes

·         Monitor treatment efficacy in patients undergoing treatment for diabetes

Understand more about Glucose - Fasting Blood

Glucose is a simple sugar or monosaccharide which is the main source of energy for all the cells of the body, and the only energy source for the nervous system. Carbohydrates consumed in the diet are broken down in the body to their simplest form- glucose, which is absorbed by the intestines and transported by the blood to various organs. Glucose is subsequently utilized by cells of these organs to produce energy wherever necessary, and the excess is stored either as glycogen in the liver for short-term storage or in fat tissues as triglycerides for long-term storage. The uptake, utilization, and storage of glucose after it is absorbed in the intestines are facilitated by the hormone- insulin secreted by the pancreas. Insulin influences the transport of glucose to the organs requiring it, like the heart, brain, working muscles, etc. It also directs storage of excess glucose. The action of insulin reduces sugar levels in the blood.

After a meal, sugar levels increase in blood and insulin is secreted in response to reduce sugar levels until it becomes normal. If glucose levels fall too low in blood, another pancreatic hormone called glucagon is released, which directs the liver to convert stored glycogen into glucose and release it into the blood. The insulin and glucagon hormones create a feedback mechanism to keep blood glucose levels within the normal range. Imbalance in their activity causes an excess or shortage of blood sugar.

The fasting glucose test checks the level of blood sugar levels during a period of fasting. This helps to determine if the body is able to utilize or store glucose efficiently. Excess sugar in blood indicates it is not being utilized or stored. This is principally caused due to Diabetes. Type 1 Diabetes is caused when insulin is not produced or produced in very little quantity. Type 2 Diabetes is caused when insulin produced is not utilized effectively by the body. In both these cases, blood sugar level rises, while cells are deprived of nutrition.

What Results of Glucose - Fasting Blood mean?


Normal fasting glucose range: 70 to 99 mg/dL (3.9 to 5.5mmol/L)

Prediabetes: 99 to 126 mg/dL (5.5mmol/L to 7.0mmol/L)

Diabetes: Higher than 126 mg/dL (7.0mmol/L) in multiple subsequent tests

Patient Concerns about Glucose - Fasting Blood

Frequently Asked Questions about Glucose - Fasting Blood

Q. How is this test performed?
This test is performed on a blood sample. A syringe with a fine needle attached is used to withdraw blood sample from a blood vessel in your arm generally from the inner side of the elbow area. The doctor, nurse or the phlebotomist will tie an elastic band around your arm which will help the blood vessels to swell with blood and hence makes it easier to withdraw blood. You may be asked to tightly clench your fist. Once the veins are clearly visible, the area is cleaned with an antiseptic solution and then the needle is inserted into the blood vessel to collect the sample. You may feel a tiny pinprick during the procedure. Blood sample once collected is then sent to the laboratory.
Q. Is there any risk associated with this test?
There is no risk associated with the test. However, as this test involves a needle prick to withdraw the blood sample, rarely, a patient may experience increased bleeding, hematoma (blood collection under the skin) formation, bruising or infection at the site of needle prick.
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The CLINICAL LABORATORY of Shahbazker’s Diagnostics Pvt. Ltd., Colaba is the 5th lab in Mumbai & 21st in India to be granted accreditation by NABL, and the 1st Lab in Mumbai and 2nd in India to be accredited under ISO 15189 (specific for medical Laboratories). NABL is a body under the Ministry of Science and Technology, Government of India. Its criteria are based on ISO 15189:2007.

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