Stability of blood ammonia at ambient temperature (version 1)
Research type
Research Study
Full title
Stability of blood ammonia at ambient temperature
IRAS ID
292835
Contact name
Ann Bowron
Contact email
Sponsor organisation
The Newcastle upon Tyne Hospitals NHS Foundation Trust Newcastle Joint Research Office
Duration of Study in the UK
0 years, 2 months, 30 days
Research summary
Ammonia is highly neurotoxic and increased blood levels may cause progressive neurological disease developing quickly to coma and death. Measurement of ammonia in blood samples is therefore important to identify elevated levels so that treatment can be commenced immediately. Ammonia increases in blood samples at ambient temperature, so laboratories historically have insisted that samples are sent promptly on ice and have rejected samples which do not meet these criteria. If ice is not available, or sample transport is delayed this could result in a diagnosis of elevated ammonia being delayed and serious neurological damage. There is no data on stability of ammonia in unseparated samples collected using modern techniques and automated sample analysis so it is unknown whether strict adherence to historical practices is necessary.
This study aims to investigate stability of ammonia in unseparated blood samples stored at ambient temperature to determine whether it is valid to report results from samples sent to the laboratory without ice or with transport delays.
Ten healthy volunteers (laboratory staff) will be recruited to the study. They will be invited to provide informed consent for blood samples to be taken via one venepuncture. Blood samples (15 ml) will be taken for ammonia analysis by a nurse or phlebotomist competent in venepuncture into 1 ml sample tubes containing EDTA anti-coagulant. One sample will be centrifuged and plasma ammonia analysed immediately (baseline) and the others stored at ambient temperature before centrifugation and plasma ammonia analysis at intervals up to 120 minutes. Participants will have no further involvement in the study.
Stability of ammonia will be assessed using a published protocol which compares results at intervals with baseline values This will provide evidence for sample stability which can be used in national guidelines for ammonia analysis.REC name
HSC REC A
REC reference
21/NI/0058
Date of REC Opinion
9 Mar 2021
REC opinion
Favourable Opinion