Ammonia detection in whole blood has applications in the diagnosis and management of many hepatic diseases, including cirrhosis and rare urea cycle disorders. Current techniques for ammonia measurement suffer from limited range, poor resolution, false positives or large, complex sensor set-ups. The current project is undertaken to develop a method and a disposable single-use point of care device for ammonia testing in blood including all chemical reagents. The aim is to develop a technique utilizing inexpensive reagents and simple methods for detecting ammonia in minimum volume of whole blood. Since, we aim this kit to be used at the source with minimum laboratory procedures and no sample processing steps. Hence, the present study will aim to develop methods to separate or withhold red blood cells or impurities in the blood sample that could adversely affect the measurement of ammonia. The sensor would exploit the modified form of the indophenol reaction, which resists sources of destructive interference in blood, in conjunction with a filter membrane. The product will have a sensing scheme that is selective against other amine containing molecules such as amino acids and has a shelf life of at least 50 days. Additionally, the resulting system will be modified to have high sensitivity and allows for the accurate reliable semi-quantification of ammonia in whole human blood samples at a minimum range of 25 to 500 μM, which is clinically relevant for rare hyperammonemic disorders and liver disease.