Sensitivity And Specificity Of Enzyme-linked Immunosorbent Assay And Immunochromatography In Detecting Serum And Urine NGAL In IgA Nephropathy

Objective To compare the sensitivity and specificity of enzyme-linked immunosorbent assay and immunochromatography in detecting serum and urine NGAL in patients with primary Ig A nephropathy.Methods There were two groups in this study: Ig A patients(n=59)that were diagnosed by renal biopsy in the Department of Nephrology of Ningxia Hui Autonomous Region People's Hospital from April 2016 to September 2019,and control group(healthy people n=30)that were randomly selected from the physical examination center.The NGAL values of serum and urine samples were detected by ELISA and immunochromatography.The clinical data of Ig AN patients and healthy controls were collected,and the risk factors of Ig AN related clinical and pathological progress,such as hematuria,proteinuria,hypertension,mesangial cell proliferation,tubular atrophy or renal interstitial fibrosis,etc.Two samples of Mann Whitney U-test and ROC curve analysis were performed for the data.Results 1.The age of Ig AN patients was 14-67(39.98±12.79)years,mainly between 20-50 years.There were 33 males and 26 females,and the sex ratio was 1.27:1.Clinical manifestations: 20 cases of edema(33.90%),9 cases of lumbago(15.25%);48 cases of hematuria(81.36%),52 cases of proteinuria(88.14%),32 cases of hypertension(54.24%).44 Ig AN patients with complete Oxford classification: 24 cases of mesangial cell proliferation(54.55%),12 cases of tubular atrophy or renal interstitial fibrosis(27.27%).2.Detection of Ig AN patients NGAL by ELISA: s NGAL: 669.24(41.25)(pg/ml),u NGAL: 556.94(112.79)(pg/ml),detection of Ig AN patients s NGAL by immunochromatography: 64.30(56.30)(ng/ml).Detection of healthy control group NGAL by ELISA : s NGAL: 457.39(51.22)(pg/ml),u NGAL: 431.84(74.21)(pg/ml),detection of healthy control group s NGAL by immunochromatography: 78.65(38.00)(ng/ml).The difference of s NGAL and u NGAL between Ig AN patients and healthy control group by ELISA was statistically significant(P<0.05).There was no significant difference in the detection of s NGAL between Ig AN patients and the healthy control group by immunochromatography(P>0.05).3.Detection of s NGAL by ELISA: AUC 0.977,sensitivity 94.9%,specificity 100%.The detection of u NGAL: AUC 0.894,sensitivity 72.9%,specificity 100%.Detection of s NGAL by immunochromatography: AUC 0.391,sensitivity 13.6%,specificity 96.7%.The combined detection of s NGAL and u NGAL by ELISA: AUC 0.985,sensitivity 98.3%,specificity 100%.Conclusion The sensitivity and specificity of ELISA in detecting s NGAL and u NGAL in Ig AN patients were better than that of immunochromatography.The sensitivity of s NGAL detected by ELISA was higher than that of u NGAL.The AUC and sensitivity of the combined detection of s NGAL and u NGAL by ELISA were higher than those of separate detection.