Abstract
The principle of this simple and rapid method for estimating blood ammonia concentration is the micronization and modification of Conway's method.1) A plastic plate (3×6×0.3cm) which has 5 holes (6mm diameter) is used. The top of each hole is covered with polypropylene film and pH indicator paper (BCG), and the bottom is sealed with metalic foil. 20 μl of a fresh, whole blood specimen is applied into a hole and a buffer tablet (pH 10.3) is added, and the hole is immediately sealed with the foil. Ammonia gas vaporized from blood permiates the film and changes the color of the BCG. After a 15 min. reaction period this color change is compared with the standard color chart and blood ammonia can be determined. Intrassay reproducibility of the method is observed as follows: n=14,x=160 μM, C. V.=8.2%. n=14,x=44 μM, C. V.=13.1%. The correlation between this method and the enzymatic method using GLDH is obtained as follows: n=139, r=0.86, y=0.92×+5.9. Alkaline labile amines have almost no influence on this method. These results show that this method has various clinical uses.
