RESUMO
Objective To evaluate the accuracy of different methods in detecting free amino acids in plasma.Method 40 blood samples from healthy volunteers were analyzed by an automatic amino acid analyzer ( Li+system) and the results compared with previous reports using other analyzers.Results The results ob-tained by this analyzer for major amino acids [asparagine (Asn), glutamic acid (Glu), glutamine (Gln), valine (Val), tyrosine (Tyr), phenylalanine (Phe), ornithine (Orn), arginine (Arg)] were similar with those previously reported using other amino acid analyzers ( all P>0.05 ) and liquid chromatography tandem-mass spectrometry (LC-MS/MS) (all P>0.05).Except for Glu and Tyr, the results for major amino acids showed large deviation compared to the results from high performance liquid chromatography ( HPLC) ( all P<0.05).Conclusion The amino acid analyzer (Li+) and LC-MS/MS (iTRAQ kit) could accurately detect free amino acids in plasma.
RESUMO
Objective To calculate the biological reference of plasma amino acid on L-8900 amino acid analyzer and to provide reference for clinical diagnosis with domestic reagents replacing original reagent .Methods By testing the original standards and the same batch of plasma (50 cases) ,we compared original reagents with domestic reagents for their performance (including resolution , repeatability ,accuracy ) .We tested the plasma free amino acids of 400 cases of healthy people using the domestic reagents to estab-lish biological reference interval of plasma amino acid ,and do correlation analysis between the amino acids level and liver function . Results (1)Domestic reagents showed high accuracy in the results of 5 consecutive detection of amino acids were high peak separa-tion and high peak retention time and high peak area .(2)Statistics derived biological reference interval of 19 amino acids and 10 kinds of amino acids had significant differences .(3)Correlation analysis showed that ALT and liver function were negatively corre-lated with threonine(P<0 .05) .GLU and valine ,isoleucine ,leucine were positively correlated(P<0 .05) .CHO and negatively cor-related with isoleucine(P<0 .05) .Conclusion Domestic agents can replace the original reagents ,on the basis ,the biological refer-ence intervals of plasma amino acids have great importance to clinical diagnosis and prognosis .