Abstract:

Objective To establish nano particle-enhanced turbidimetric immunoassay（PETIA） for determining serum lactate dehydrogenase isoenzyme 3（LDH₃）.Methods The optimal reaction conditions [antibody concentration,latex particle size,1-ethyl-3-（3-dimethylaminopropyl）carbodiimide（EDAC）/ N-hydroxysuccinimido（NHS） concentration,the kind and pH value of buffer solution and reaction time] were determined. PETIA for determining serum LDH₃ was established. According to the National Committee for Clinical Laboratory Standards EP5-A2,the precision,linear range,recovery rate,anti-interference ability and analytic sensitivity were evaluated,and the initial reference interval was established.Results The optimal reaction conditions were antibody concentration 0.1 mg/mL,latex particle size 120 nm,EDAC/ NHS concentration 10 mg/mL,phosphate buffered saline（PBS） with pH value 7.8 and coupling rate remaining unchanged under room temperature（25 ℃）and low temperature（4 ℃） for 24 h. For LDH3 with low value（16.5 U/L）,median value（65.0 U/L） and high value（155.0 U/L）,the within-run coefficients of variation（CV） were 5.77%,4.02% and 3.77%,and the between-run CV were 6.59%,4.44% and 3.93%. The linear range was 3.6-200.0 U/L. The average recovery rate was 102.1%. The factors of 900 U/L rheumatoid factor,500 μmol/L bilirubin,9 mmol/L triglyceride,5 g/L hemoglobin,5 g/L vitamin C had no interference for PETIA in the determination of LDH3. The analytic sensitivity was 3.6 U/L. The reference interval was 13.5-75.9 U/L. Conclusions PETIA for the determination of LDH3 is simple,rapid,sensitive and accurate,and it can be used in automatic biochemical analyzers,which can meet the requirements of clinical determination.

Key words: Lactate dehydrogenase isoenzyme 3, Nano particle-enhanced turbidimetric immunoassay, Performance evaluation