Patient’s ammonium levels can now be measured at the point of care 

Patient's ammonium levels can now be measured at the point of care

A point-of-care analyser can monitor levels of ammonium in a patient’s blood using a decentralised method that researchers have developed.  

Researchers from the Sensors and Biosensors (GSB) research group of the Department of Chemistry at the UAB, worked in collaboration with the Hospital Sant Joan de Déu and the UPC on the new device. The new point-of-care (POC) analyser can measure blood ammonium levels in any location, and location and will not require a blood sample to be sent to laboratories as is the case with traditional equipment.  

The device will be able to decentralise the blood ammonium determination. This will make it possible for smaller healthcare centres to measure ammonium through direct blood measurements without needing previous treatments.  

With the use of the new device, the number of monitoring sites could be multiplied, simplifying the process, and reducing the time needed to make medical decisions.  

Dangerous levels of ammonium can cause death

Ammonium is a biomarker that can diagnose rare hereditary metabolic disorders, such as the primary disorders of the urea cycle, and metabolic and environmental conditions affecting the liver’s function.  

An excess amount of ammonium is produced in all these disorders, creating a health risk for the patient. Levels of ammonium that surpass 200 micromoles per litre of blood are as considered severe cases of hyperammonaemia. This can cause irreversible damage to the brain and can lead to death if levels of ammonia surpass 500 micromoles per litre. 

Early diagnosis is crucial to minimising the effects of hyperammonaemia. Currently, patients diagnosed with metabolic disorders which include must attend periodic festival visits. Here, a blood sample is taken, which then must be analysed in a laboratory.  

“Increasing the frequency of blood analyses to determine ammonium levels is of vital importance”, explained UAB researcher Mar Puyol and director of the study.  

“Reducing the excess of ammonium in a patient with hyperammonaemia is done by restricting protein intake, using drugs to enhance ammonium elimination, and dialysis and hemofiltration in the most acute cases, so that the evolution of the patient will be more favourable the faster the doctor’s act, and that can be achieved by using the point-of-care analysers such as the one we have developed,” added Puyol.  

The device will go on trial in hospitals soon

The researchers are preparing a prototype that will function under semi-autonomous conditions. When the device is ready, all ammonium samples submitted for analysis each day at the Hospital Sant Joan de Déu will be measured with the conventional method and with the new equipment created by researchers for comparison.  

“Hundreds of samples will be necessary before the final prototype of the point-of-care analyser is validated. The next stage will then be industrialising the device to launch it into the market. There are still several stages before reaching that scenario, but the device is expected to become an economic alternative that can facilitate the monitoring of liver diseases in developing countries as well,” said Puyol.  

The researcher’s device will use a microfluidic platform which includes a potentiometric detection system and a gas separation membrane. This will allow the medical staff to automatically separate the ammonium from the rest of the complex matrix of blood. This can guarantee precise and exact measurements of ammonium concentration in whole blood and not in plasma, which is the method typically used to analyse this parameter. 


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