Correction of serum NSE reference intervals includes the unidentified hemolysis sample: 1‐year data analysis from healthcare individuals

BACKGROUND: Reference intervals (RIs) are important for interpretation of laboratory results. Neuron‐specific enolase (NSE) can be utilized to aid the diagnosis of various tumors. However, while red blood cells contain NSE αγ‐isozymes, unrecognized slight hemolysis will result in increasing of NSE levels in serum. The aim of this study was to correct the NSE RIs from healthcare individuals results which may have unidentified microhemolysis. METHODS: A total of 15 047 healthy individuals undergoing regular health care were recruited to redefine the NSE reference interval according to the CA28‐A3 document. Volunteers with NSE level between 16.3 ng/mL and the upper limit of new RIs were performed venipuncture for NSE retest. Simultaneously, serum free hemoglobin (fHb) was performed with o‐tolidine test. RESULTS: Reestablishment of NSE RIs is 0‐18.9 ng/mL, which is wider than 0‐16.3 ng/mL provided by the manufacturer. Seventy‐four volunteers with the NSE level between 16.3 and 18.9 ng/mL were performed venipuncture for NSE retest. The ratio of NSE level drop to normal is 85.1% (63/74) in the subsequent results; there are significant differences between the median NSE of two groups (18.15 vs 14.15 ng/mL). Subsequently, the fHb concentration of 22 healthy individuals from 74 individuals was measured; there are significant differences between the median fHb of two groups (58 vs 30 mg/L). CONCLUSIONS: Some specimens with slightly elevated NSE may be attributed to the unrecognized slight hemolysis. The correction RIs may be expected to decrease the abnormal NSE results.