The serum ammonia test measures the level of ammonia in the blood, helping diagnose conditions like liver disease or urea cycle disorders.
Serum ammonia test procedure steps for ammonia test.
- Confirm the patient’s identity using two identifiers (e.g., name and date of birth).
- Ammonia-free heparinized collection tube (usually green-top or lavender-top tube for EDTA).
- Apply a tourniquet to the upper arm to make the vein more prominent. Avoid prolonged use, as it can affect ammonia levels.
- Disinfect the venipuncture site with an alcohol swab, allowing it to dry.
- Use a sterile needle and syringe or vacuum system to collect the blood sample. Avoid hemolysis, as it can falsely elevate ammonia levels.
- After collecting the sample, withdraw the needle, apply pressure to the puncture site with gauze, and secure with adhesive tape.
- Transfer sample Immediately otherwise place the sample tube in an ice slurry to prevent degradation of ammonia.
Lab Analysis steps
- Add 200 µL of R1 reagent into the reaction cuvette or test tube.
- Add 5 µL of the sample to R1.
- Mix gently and incubate for 2–5 minutes at 37°C to allow initial stabilization.
- Add 50 µL of R2 reagent to the mixture. Mix again and incubate according to the kit instructions (e.g., 5–10 minutes at 37°C).
- Measure absorbance at the specified wavelength (e.g., 340 nm).
Precautions
- Ensure the patient avoids strenuous exercise before the test, as it can increase ammonia levels.
- Avoid smoking or alcohol consumption prior to the test, as they can also interfere with results.
- Delay testing if the patient has undergone recent physical trauma or surgery, as these conditions can affect ammonia levels.