Difference between Urine & Blood Glucose - Sugar.Fit
Metabolic Health

Urine Glucose & Blood Glucose - Know The Difference

When a person with diabetes approaches us for assistance in managing and reversing the condition, one of the questions we come across is, “What is the difference between blood sugar and urine sugar?” The answer to this is simple. Glucose (sugar), whether in blood or urine, is the same. But the reason it has manifested in urine can be different from that of blood sugar. 

The presence of a high amount of sugar in our blood leads to diabetes, whereas a similar spike in urine sugar leads to a condition known as glycosuria. It is important to understand that while diabetes remains the primary reason for glycosuria (also known as glucosuria), it is not the only one. Renal failure or complications, and eating food that triggers a sudden spike in sugar release, can also lead to glycosuria. 

What is Glycosuria?

Usually, there is little to no sugar in urine of a healthy person. However, when one has glycosuria, there is a significant amount of glucose present in the urine. This may be an indication of underlying issues but most people find out regarding glycosuria only after taking a urine test. The most common cause of Glycosuria is diabetes. The excess sugar in the body is passed out through the urine.

How Glucose Gets into Urine?

Some amount of sugar in your urine is normal. However, in the case of glycosuria, the normal glucose urine range of 25 mg/dL gets exceeded. Kidneys filter the waste from the body and remove it from the bloodstream. Glucose is removed from the bloodstream by kidneys and supplied back to the body. Most of the glucose is reabsorbed by the body. The remainder is expelled through urine but when the kidneys cant remove sugar from the blood in time, the quantity of glucose in urine increases. 

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What can cause a spike in Urine Sugar?

The most commonly observed causes for a spike in sugar level in urine are type 1 and type 2 diabetes. 

  • Type 2 diabetes - In type 2 diabetes, the pancreas does not create enough insulin or the body becomes resistant to insulin. Due to this, the body is unable to control glucose levels in the blood. When the blood sugar rises, the kidneys cannot redirect back to the blood and the extra gets thrown out of the body through urine. 
  • Type 1 diabetes - Type 1 diabetes is a progressive destruction of particular cells in the body that result in decreased insulin production. Lower levels of insulin automatically mean higher levels of glucose in the blood and more glucose in urine. 
  • Kidney disease - Any issue with the kidneys, especially renal glycosuria, which is a genetic condition can cause a spike in glucose in urine. Renal glycosuria is a genetic or an acquired condition. When the kidneys are damaged, they cannot filter out the glucose from the blood and the glucose gets expelled from the body through urine.

Sources of Glucose

The main source of sugar in our bodies is the food we eat. Our diet invariably consists of large portions of carbohydrates, which get broken down into sugar to power up our cells and the brain for bodily functions. The insulin kicks in to monitor and manage the sugar release and aids its absorption. 

Sugar is found in all kinds of natural and processed food around us. Fruits such as mangoes and pomegranates, and vegetables such as potatoes have a high sugar load. Most baked products, confectionery and carbonated drinks are high in sugar. But these are add-on sugars, which the body does not need and, therefore, lead to a build-up of excess blood and urine sugar.  

Sugar is also released into our system by the liver, which stores excess discharge into the bloodstream. Consider it a warehouse that stocks up sugar as glycogen. When your blood glucose level starts dropping, the liver releases the stored sugar back into the bloodstream to fuel bodily needs. 

Functions of Glucose

Along with amino acids and fats, glucose is the primary fuel source that drives metabolism and powers up our brain and muscles. We must know that the human body is designed to use glucose for its day-to-day functions. 

  • Our brain will be confused and in disarray without an appropriate dose of sugar. This is because, unlike the liver, the brain cannot store sugar. A steep drop in sugar level (Hypoglycemia) can result in disruption of motor functions. An acute condition can also lead to coma. 
  • Muscle fatigue would set in if sugar levels plummet in the body. During exercises or tasks involving physical labour, muscles draw up fuel from glycogen stored in them. A sudden depletion of glycogen can result in cramps and fatigue. 
  • Collagen for skin, red and white blood cells, and glycoproteins that help in neuronal development, require sugar to work.

Difference between blood glucose and urine glucose

Blood Glucose

A minimal presence of glucose in our bloodstream is actually desirable and vital for a healthy and active lifestyle. After all, it powers our everyday activities. Once we are aware of blood glucose levels and how they affect our body, the difference between blood sugar and urine sugar also becomes clearer.

Blood glucose is a term used to define the measure of glucose or sugar in the bloodstream. This can be measured before and after meals. Blood sugar levels between 80 and 140 mg/dL (milligrams per decilitre) in a random test are considered to be normal. The corresponding values of lower and higher sugar presence than this range is worrisome and can lead to hypoglycemia and hyperglycemia, respectively. 

When the latter develops as a chronic condition, it results in diabetes. We have started to recognise persons with sugar levels in the blood up to 200 mg/dL in the prediabetes stage. This allows us to monitor a person’s health and offer a course correction to reverse the onset of prediabetes. A consistent reading above 200 mg/dL is a sure sign of diabetes and needs medical intervention for timely management and cure. 

Urine Glucose

Before blood glucose measurement became the universal standard in defining a person with diabetes and prescribing a line of treatment, a urine glucose test was conducted to evaluate the high levels of sugar in the body. Today, a urine glucose test is advised by physicians for subjects with Type-1 diabetes or when the sugar levels in a person without any history of diabetes turn up abnormally high. 

When blood sugar remains consistently high, it tends to crop up in our urine, with the kidneys trying to flush it out. The presence of sugar levels in urine is called glycosuria. We recommend that a urine sample without any presence of sugar is the best. Sugar levels up to 0.8 mmol/L (millimoles per litre) are considered normal in urine. If the values are higher, one must consult a physician to find out the underlying cause of urine sugar. For people with diabetes, high urine glucose is a warning to get their sugar levels under control. 

If the spike in urine sugar does not correspond with the results of a blood sugar test, the doctor will look for other reasons, such as renal glycosuria. Pregnant women can have high urine sugar, and so can anyone on a regular diet of high-sugar foods. In some cases, urine sugar is analysed to treat Urine Tract Infection. These can be addressed separately, but a urine sugar test by itself is inconclusive so far as determining diabetes in a person is concerned.

What is Renal glycosuria?

Renal glycosuria is a genetic condition in which your body gets rid of glucose even though there is no excess of it. If you get a blood test done, you will be absolutely fine but a urine test will show a spike in blood sugar levels. The defect is in the part of the kidneys that is responsible for absorbing glucose from the bloodstream.

Types of Renal glycosuria?

There are categories of glucosuria based on the rate of reabsorption by the kidneys, and renal threshold. There are 3 categories of benign glycosuria - 

  1. Type A - This is the most commonly observed type. There is a decline in the renal threshold and maximal glucose reabsorption rate. 
  2. Type B - The rate of reabsorption is normal but there is a decline in the renal threshold. 
  3. Type O - Glucose reabsorption does not happen in kidneys. There is a lot of glucose excreted even though the blood glucose, glucose tolerance and insulin levels are normal.

Measuring sugar in your urine yourself

Those with diabetes need to keep a close watch on their blood glucose levels as well as glucose levels in the urine. It is difficult to determine by the appearance of the urine if you are wondering “What does sugar in urine look like?” The best way to measure sugar urine yourself is to get a home test kit and do the urine sugar test at home. 

The kit contains test strips which are easy to use. You can measure sugar in your urine yourself by collecting the sample in a container and dip the test strips in the sample. It may take upto 2 minutes for the strip to change color, as the glucose in urine causes a reaction, and shows the results. It is advised that you should test with urine that has not been in the bladder for long. SO avoid testing with the first urine of the day. Instead collect samples of the one that has formed in the last hour to get an accurate result. It is recommended that you ask a doctor regarding the best time to collect the sample and test the urine yourself.

FAQs

Why would urine glucose be higher than blood glucose?

The glucose levels of your body are the same in urine and blood however, when too much glucose is present in your blood then to get rid of the extra glucose in the body the kidneys will produce urine that contains glucose so that it can easily get rid of the higher glucose that was present in the blood. Such a condition where too much sugar is present in your urine causes a diabetic complication called glycosuria.

Why is blood glucose testing better than urine glucose testing?

The accuracy that blood glucose tests provide is more precise than the accuracy provided by urine glucose tests, for this reason, doctors mostly use blood glucose tests to diagnose diabetes. To precisely measure the glucose levels in a person, blood glucose tests are more reliable and measure exactly the amount of glucose present in your body. To arrive at proper conclusions blood glucose tests are preferable.

Bottomline

Sugar or glucose is the primary fuel for our physical and mental activities. Its presence is, therefore, a given in the bloodstream. But higher values of blood sugar are unhealthy and are indicative of diabetes. The difference between urine sugar and blood sugar is that the detection of glucose in the former warns of a spillover effect. Glycosuria most certainly means the body is trying to flush out excess glucose. A physician will determine whether it is a result of diabetes, a renal complication, or any other condition, including a bad diet. Want to know more about diabetes? Book an appointment with our experts to understand how blood and urine sugar levels can be normalised by adopting a healthy lifestyle. 

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