Random Blood Sugar Test

random blood sugar test

Last Updated December 20th, 2021

What is a random blood sugar (RBS) test?

A random blood sugar test is a test carried out to measure the levels of glucose in your blood.

Glucose– It is a carbohydrate belonging to the class of monosaccharides. In fact, it is the amplest monosaccharide. It is a simple sugar and its name is derived from the ancient Greek word gleukos which means “sweet delightful wine.” Plants manufacture glucose during photosynthesis with the assistance of energy from the sun. 

Our body needs glucose as the principal source of energy. It is derived from the food we eat. Heart, brain, kidneys, and muscles are among a few principal organs of our body that are dependent on a constant supply of glucose to function optimally.

What is diabetes mellitus?

Diabetes mellitus– Diabetes mellitus is a chronic illness in which your body either doesn’t make insulin or your body’s ability to utilize insulin is impaired. The outcome is same-increased blood sugar levels. Diabetes mellitus can be broadly classified into the following categories-

Type 1 diabetes- also known as insulin-dependent diabetes mellitus (IDDM). In this case, the beta cells of the pancreas which produce insulin are destroyed due to autoimmune irregularity. This results in a deficiency of insulin in the body.

Type 2 diabetes- also known as non-insulin dependent diabetes mellitus (NIDDM). In this scenario, the cells of your body become resistant to the effects of insulin. It’s the most common type of diabetes. It was earlier known as adult-onset diabetes, but its incidence has been on the rise in children of late; the primary reason is a surge in childhood obesity.

Gestational diabetes mellitus (GDM)- It is a type of diabetes that manifests itself during the second or third trimester of pregnancy.
Diabetes is secondary to other underlying conditions such as cystic fibrosis, pancreatitis, drug-induced diabetes (e.g. steroid-induced diabetes), monogenic diabetes syndromes, and following organ transplantation.

Insulin– It is a hormone secreted by the beta cells of your pancreas and is important for the metabolism of glucose that is derived from foods that you eat. Insulin keeps the blood sugar levels within the normal range. This is branded as endogenous insulin. Exogenous insulin is the one that is used therapeutically in patients suffering from diabetes.

Why has my physician asked me to undergo a random blood sugar?

Your physician may ask you to undergo a random blood sugar test if you present with the following features-

– Increased thirst (out of proportion to the intake of water)
– Increased appetite despite adequate consumption of food
– Headaches
– Lapses in concentration
Distorted vision.
– Frequent urination
– Lethargy
– Unexplained weight loss
– Susceptibility to infections
– Impaired healing of wounds
RBS is the test performed in emergency settings when a patient must be taken up for an urgent, unplanned operative procedure. RBS test can also be used for serial monitoring of the blood sugar status of a diabetic daily by using a do-it-yourself kit.

Do I need to fast before the RBS test?

There is no need to fast before undergoing a random blood sugar test. This test, as the name implies, is a random test that can be conducted anytime, irrespective of the fasting status of the individual.

Can I undergo an RBS test if I am pregnant?

Yes, it is safe to undergo random blood sugar if you are pregnant. The procedure is safe and there is no risk involved for the pregnant female or the unborn fetus. You can also undergo an RBS test if you are lactating and breastfeeding your child.

Can children undergo RBS test?

Yes, children can undergo the RBS test as it is a safe, and risk-free test.

How should I prepare for the RBS test?

No specific preparation is required. You need to discuss with the physician your medical history as well as family history. As RBS test is a blood test and involves the standard techniques of venipuncture, you need to inform your physician if-

– You are taking any blood thinners
– You are suffering from any coagulopathy
– You also need to give your physician in-depth information regarding the medicines (including ayurvedic, homeopathic, supplements) that you might be consuming. Many medicines including steroids have the potential to hamper the results of the RBS test by either elevating or decreasing the glucose levels in the blood depending on the drug’s profile.

Are there any risks involved?

There are no serious complications of oral glucose tolerance test. It is a minimally invasive procedure. Rare instances of bruising, bleeding and subsequent infection at the site from where blood is withdrawn have been reported. Slight dizziness may be encountered when the vein is punctured or at the site of blood collection.

Is there any contraindication for RBS test?

There are no absolute contraindications to the RBS test. However, if you are suffering from a coagulopathy or are on blood thinners, your physician may avoid making you undergo this test for the fear of a bleeding complication.

How is the RBS test performed?

A random blood sugar test is performed as an outpatient procedure. It is a safe, minimally invasive and quick test. No sedation is given. The test can be carried out in a doctor’s office or at a diagnostic center. If you are already admitted to a hospital, this test will be carried out in a hospital setting itself. The test involves the following simple steps-\

– You will be escorted to the collection site (an area in the lab/hospital for collecting specimens for testing).

– You will be asked to sit on a comfortable chair or lie down on a hospital bed.

– A technician will apply a tourniquet proximally to the site chosen for venipuncture. This makes the veins more prominent, allowing easier access.

– The area is cleaned with a disinfectant.

– A sterile needle is used to puncture the vein and draw blood.

– The pressure is applied to the vein with sterile gauze after the needle is withdrawn.

– The tourniquet is released.

– The blood sample is collected in a vial.

– A small bandage is applied over the site from where blood has been drawn.

An RBS can also be safely performed in the home-setting by the patient using a simple kit which includes a finger prick device (lancet) and a glucometer.

How long does the RBS test take?

The process of random blood sugar testing does not take more than 5-10 minutes. However, in certain cases, venous access may be difficult to obtain; young children, obese patients and patients belonging to the geriatric age group are a few examples. In these circumstances, more than 1 prick may be required while withdrawing venous blood for sampling, thus increasing the procedure time.

When can I get the results of my RBS test?

You can get the results of random blood sugar test on the same day.

What do the results of the RBS test convey?

A reading of 200 mg/dL or above while preforming an RBS test is indicative of diabetes mellitus. The test may be repeated by the physician the next day before arriving at a diagnosis. Moreover, glucose tests such as FBS, and OGTT are required for a final verdict of diabetes mellitus to be arrived at.

What is the cost of the RBS test in India?

The cost of a random blood sugar test in India is around Rs 150. The actual cost may vary depending upon the city you reside in or the healthcare provider that you choose.

What are the advantages and limitations of RBS test?

Advantages Limitations
RBS is a simple, easy to perform and risk-free test. Valuable when a quick diagnosis of diabetes is required and in emergency settings. As it is a blood test involving venipuncture, it cannot be performed in patients suffering from bleeding disorders.
It can be used any time during the day and no fasting is required. It cannot be used as a substitute for other blood tests-FBS, GTT or HbA1c. 
It is safe to be used in pregnancy, lactation and in children.The results can be hampered by the concomitant intake of certain drugs.
The ease of doing it in home-settings makes it a patient-centric test.Exercising before an RBS test can lead to an inaccurate reading. Moreover, instructions need to follow diligently while performing a hone-test.

What are the other tests used to analyze blood sugar levels?

Apart from the random blood sugar test that we have discussed above, diabetes mellitus can also be diagnosed by anyone of the following blood tests:

Fasting blood sugar test Two successive values of this test that are equal to or greater than 126 mg/dl confirm diabetes mellitus.

Glycosylated hemoglobin testA value equal to or greater than 6.5 percent is confirmative. This test holds significance as it conveys a three-month average of blood sugar status of your body.

A two-hour oral glucose tolerance test (GTT)with any value over 200 mg/dl clinches the diagnosis.


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