Simultaneous detection of carcinoembryonic antigen and neuron-specific enolase in human serum based on time-resolved chemiluminescence immunoassay.
Mao Yanhua,Wang Nana,Yu Fei,Yu Songcheng,Liu Lie,Tian Yongmei,Wang Jia,Wang Yilin,He Leiliang,Wu Yongjun
The Analyst
In the clinical diagnosis of tumor, the immunological detection of single tumor markers may lead to errors and missed inspection. Therefore, it is necessary to establish an accurate and effective method for the simultaneous detection of multiple tumor markers. Thus, we developed a time-resolved chemiluminescence immunoassay (TRCLIA) to simultaneously detect carcinoembryonic antigen (CEA) and neuron-specific enolase (NSE) in human serum. Horseradish peroxidase (HRP) and alkaline phosphatase (ALP) were used as the detection probes to label the monoclonal antibodies of CEA and NSE by strain-promoted azide-alkyne cycloaddition (SPAAC), respectively. Based on a sandwich immunoassay, the targets in the samples were captured by antibodies immobilized on the surface of carboxylate-modified polystyrene microspheres (CPSMS) and sandwiched by other antibodies labeled with HRP and ALP. Since HRP and ALP had different dynamic characteristics, the CEA and NSE signals were recorded at 0.5 s and 20 min, respectively, and cross-interference could be avoided effectively. The whole signal detection processes could be completed in 20 min. The linear ranges of CEA and NSE were 0.1-64 ng mL-1 and 0.05-64 ng mL-1 and the limits of detection were 0.085 ng mL-1 and 0.044 ng mL-1 (S/N = 2), respectively. Also, 45 human serum samples obtained from patients having lung disease were tested by TRCLIA and commercial chemiluminescence enzyme-linked immunoassay (CLEIA) kits with good correlation. The correlation coefficients of CEA and NSE were 0.985 and 0.970, respectively. The results demonstrated a novel, effective, reliable and convenient TRCLIA method for the clinical diagnosis of CEA and NSE. The TRCLIA method has the potential to be an effective clinical tool for the early screening of lung cancer and can be applied in clinical diagnosis.
10.1039/c9an00910h
Development and validation of a simple correction method for the measurement of neuron-specific enolase in hemolyzed serum samples.
Scandinavian journal of clinical and laboratory investigation
The Neuron-specific enolase (NSE), a biomarker of neuroendocrine tumors or ischemic brain damage, has limited clinical applicability since its measurement is overestimated by hemolysis. In this study, an NSE correction method was developed for hemolyzed samples. The NSE concentration and the hemolysis index (HI) of serum were measured before and after spiking a hemolysate prepared with red blood cells from the serum-separating tube and extrapolating the NSE value corresponding to a HI of zero. To validate the approach (n = 46), NSE concentrations and HI were measured before (NSE0 and HI0) and after spiking the samples with 50 µL (HIA, NSEA) and 100 µL (HIB, NSEB) of hemolysate. A linear regression analysis was performed between (HIA, NSEA) and (HIB, NSEB). The y-intercept was taken as the corrected NSE concentration (NSEintercept) and compared with NSE0. On the same samples, the equation of Tolan et al. was applied and the corrected values of NSE (NSEcorr) were compared to NSE0. The average bias (±SD) between the NSE0 and the NSEintercept was equal to -3.2% (± 14.3) versus 34.6% (± 19.8) against the NSEcorr. Applying the allowable total error proposed by the European Federation of Laboratory Medicine, 72% of the NSE results were adequately corrected while the reference method corrected only 8.7% of the results. The individualized hemolysis correction method developed is simple, fast, requires one serum-separating tube, provides increased accuracy compared to the method described by Tolan et al. and should improve the quality of patient care.
10.1080/00365513.2021.2009021
Invisible hemolysis in serum samples interferes in NSE measurement.
Tumori
INTRODUCTION:The accuracy of serum neuron-specific enolase (NSE) measurements is critical, particularly in neurologic diseases and cancer. NSE measurements are compromised by slight, even invisible, hemolysis, which can produce apparently higher NSE levels, leading to inappropriate clinical decisions. In this article, we describe this issue and propose a solution for avoiding incorrect results. METHODS:Twenty blood samples from donors with NSE values that were within the reference interval were considered. Experimental hemolysis was induced in vitro to examine the relationship between the degree of hemolysis and the increase in serum NSE. The data were then subjected to statistical analysis. RESULTS:There was excellent correlation ( 0.953) between the degree of hemolysis and the rise in NSE concentration. Each hemolysis unit (equal to 1 mg/dL of free hemoglobin) corresponded to a mean value of 0.29 ± 0.09 ng/mL NSE that was released from red blood cells. CONCLUSION:The hemolysis index must be measured in every sample with no evident hemolysis before assaying it for NSE. Moreover, if the degree of hemolysis is between 5 and 30 units, the increase in NSE (from 1.5 to 9.0 ng/mL) must be calculated, and the laboratory results should be appended with comments that suggest the approximate rise in NSE.
10.1177/0300891619867836
Distribution of serum neuron-specific enolase and the establishment of a population reference interval in healthy adults.
Liu Qian,Fan Jilong,Xu Aiguo,Yao Li,Li Yan,Wang Wenjun,Liang Wei,Yang Fumeng
Journal of clinical laboratory analysis
BACKGROUND:Neuron-specific enolase (NSE) is an important tumor marker in the serum of patients with lung cancer. Elevated serum NSE levels are also associated with many other diseases. However, there is no unified population reference interval for serum NSE. This study aimed to investigate the distribution of serum NSE in healthy Chinese adults aged 20-79 years and to establish its reference interval in Chinese population. METHODS:A total of 10 575 healthy subjects were in line with the requirements of this study. The concentration of serum NSE was detected by a fully automated Cobas e602 analyzer with matching reagents. The population reference interval for serum NSE was established using the unilateral 95th percentile (P ) according to standard guidelines. RESULTS:The distributions of serum NSE were not significantly different between males and females (P > 0.05) and also did not differ by age (P > 0.05). Therefore, the population reference interval for serum NSE was established as upper limit 25.4 ng/mL (90% confidence interval: 24.5-26.2 ng/mL). CONCLUSIONS:We established the first population reference interval for serum NSE in a large healthy Chinese adult cohort, which was higher than that recommended by Roche Diagnostics GmbH. This new reference interval is more practical and applicable in Chinese adults.
10.1002/jcla.22863
Correction of serum NSE reference intervals includes the unidentified hemolysis sample: 1-year data analysis from healthcare individuals.
Xie Erfu,Zhang Wei,Xu Huaguo,Ling Yun,Zhang Qiaodi,Pan Shiyang
Journal of clinical laboratory analysis
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.
10.1002/jcla.22997
Establishment of Reference Intervals for Serum Cytokeratin-19 Fragment and Neuron Specific Enolase by Indirect Method Using Data Obtained from Healthy Chinese Population in Chengdu.
Zhen Sheng-Hang,Wang Yan,Gu Chang-Guo,Liu Ding,Shen Xu-Xia
Clinical laboratory
BACKGROUND:In order to establish suitable reference intervals (RIs) of serum cytokeratin-19 fragment (Cyfra211) and neuron specific enolase (NSE) for the healthy Chinese population in Chengdu, China, an indirect method was developed using the data from the people presented for routine health check-up. METHODS:All results for 4,988 healthy persons serum cytokeratin-19 fragment and 3,293 healthy persons neuron specific enolase were collected in our laboratory information system between January 2016 and December 2018. Outliers were identified and excluded using the stem-and-leaf and box plot methods. Mann-Whitney U test was used to observe the difference between sexes. Spearman's rank correlation analysis was used to evaluate the correlation between serum results and age. The RIs were defined by nonparametric 95th percentile interval. RESULTS:After statistical analysis the indirect RIs were 0.0 - 3.70 ng/mL (Cyfra211) and 0 - 17.26 ng/mL (NSE) in males and 0.0 - 3.35 ng/mL (Cyfra211) and 0.0 - 16.29 ng/mL (NSE) in females. Cyfra211 and NSE levels in males and females had no correlation with age. Therefore, there was no need to establish RIs according to age group. RIs of Cyfra211 and NSE were verified and passed the verification in the end. CONCLUSIONS:Using health check-up persons' laboratory data values is a relatively easy and cheap method of establishing laboratory specific references. This method deserves to be promoted and applied by other clinical laboratories.
10.7754/Clin.Lab.2019.190113