Background: Blood ammonia detection is used for the diagnosis or differential diagnosis of various hepatitis virus infections, severe liver cirrhosis, and hepatic encephalopathy. It is also one of the important indexes reflecting liver coma, Reyes syndrome, and other diseases. However, blood ammonia changes rapidly with time. If samples are not sent and detected in time, the results will be wrong, resulting in clinical misdiagnosis and life danger to patients. The purpose of this paper is to explore the change of blood ammonia with time and establish its reference interval.
Methods: For this study, 228 healthy patients (111 males and 117 females) were selected who underwent physical examination at the Health Management Center of the Second Xiangya Hospital of Central South University from April to May 2021. The blood ammonia detection kit (colorimetric method) produced by Roche Diagnostics GmbH of Germany was used for detection on the Roche cobas c702 automatic biochemical analyzer. After eliminating outliers from the obtained test results, they were grouped according to gender and age, and SPSS 26.0 software was employed to statistically analyze the blood ammonia test results.
Results: The differences in blood ammonia levels at each detection time were statistically significant (p < 0.05). The differences in blood ammonia levels between male and female subjects at 1 hour, 2 hours, and 3 hours were statistically significant (p < 0.05), but all ages saw no statistically significant difference in blood ammonia levels between segments (p > 0.05). The blood ammonia levels of each detection time and different genders showed a normal distribution. Therefore, it is necessary to take the 95% (X ± 1.96S) results of both sides as the reference interval according to the detection time and gender, and establish the reference intervals. The 1-hour blood ammonia reference interval for healthy men in Changsha is 15.8 - 47.5 μmol/L, for healthy women it is 12.4 - 39.6 μmol/L; the 2-hour blood ammonia reference interval for healthy men is 22.3 - 56.5 μmol/L, and for healthy women it is 19.1 - 48.0 μmol/L; the reference interval of 3-hours blood ammonia for healthy men is 27.9 - 65.7 μmol/L, and for healthy women it is 24.6 - 56.7 μmol/L.
Conclusions: There are differences in blood ammonia levels between men and women at different detection times in Changsha. A reference interval suitable for blood ammonia in healthy individuals in the region should be established according to the detection time and gender, so as to provide better relevant evidence for clinical diagnosis.