Uric Acid Test: All you need is a piece of paper

You may soon be able to check your blood's uric acid level while sitting in the comfort of your own home!

One may no longer have go to a pathology laboratory or give a blood sample for the diagnosis. Just a piece of specialised paper is all that would be needed to gauge the level of uric acid in your body or even your kidney condition.

A team of researchers at Bangladesh University of Engineering and Technology has invented such a paper, making checking uric acid levels much easier.  

All one needs to do is put a drop of urine on the specialised paper -- a simple, low-cost, instantaneous and user-friendly paper based analytical device (PAD) for the qualitative and quantitative detection of uric acid in urine -- and the colour of the paper will tell the rest.

The invention is still in the early development phase but the inventors have already applied for a patent for it.

Mohidus Samad Khan, the lead researcher and assistant professor of the chemical engineering department of the Bangladesh University of Engineering and Technology, said the growing number of kidney patients in Bangladesh was the driving force to conduct such a study.

Urinary or serum uric acid concentration is an indicator of chronic kidney conditions. Thus, detecting its presence can go a long way towards treating the conditions.

Uric acid is a waste product of human metabolism, and is normally excreted out through urine. But if too much uric acid is produced and insufficiently excreted, it accumulates in the body by forming crystals and settles in the joints, soft tissues or organs, eventually leading to the disease known as gout.

The inventors said this paper-based method was faster and cheaper than traditional detection techniques.

“It would cost less than Tk 5,” Mohidus said. In any lab, the cost for the test is at least Tk 250.

Although the method doesn't give an exact figure, it does give an indication.

Kaoser Alam, a physician at Bangabandhu Sheikh Mujib Medical University, said, “Usually we do blood tests to see the uric acid level. It is possible to know the [level of] uric acid from a urine test but it does not give exact information. To know the uric acid level and gravity of the problem, blood test is a must.”

HOW IT WORKS

To form the paper based diagnostic device, first a piece of paper was pasted with potassium ferricyanide reagent and then the urine sample was applied on the paper surface, Mohidus said.

“Then that paper would be dipped into a capsule like device where ferric chloride reagent was kept. Uric acid in the urine sample reacted with ferricyanide solution to produce ferrocyanide which then reacted with ferric chloride and produced Prussian blue colour signals on the paper surface. The higher the uric acid concentration in the urine sample, the stronger the colour signals it produced on paper.

"...with proper calibration, the paper-based technique can be compatible and economical [compared] to the sophisticated detection techniques used to detect urinary uric acid.”

The lead researcher said to get the representative value, the urine should be preserved for 24 hours.

The colour signal produced on the paper can be analysed with the help of camera enabled mobile devices, computers or electronic gadgets. The test can also be integrated with a smart phone camera, or those of computers or laptop, and an image processing application (using windows/android/IOS platform) as a part of digital diagnostics.

The results can be stored in the device to monitor urinary uric acid level trend over time and can be sent to an established medical facility for further analysis.

Using the proposed technique, patients can regularly (daily or weekly) monitor their urinary uric acid level at home.

If the level is frequently found close to or higher than the acceptable limit, the patients can take necessary steps to reduce it by changing their diets and lifestyles, or by consulting a doctor for further analysis and advice.

“This technique will also facilitate physicians and dieticians to monitor and medicate kidney conditions of their patients,” Mohidus added.

He said they would go for commercial production soon after consulting with some pharmaceuticals company, adding that commercial design of the product would allow users to add reagents manually or automatically.