Establishment of a time‐resolved immunoassay for acute kidney injury based on the detection of Kim‐1

Abstract

Aim To establish a highly sensitive time‐resolved fluorescence immunoassay (TRFIA) of kidney injury molecule‐1 (Kim‐1) and evaluate its clinical value in acute kidney injury (AKI). Methods The Kim‐1‐TRFIA was established by the double‐antibody sandwich method, and the method was evaluated. The established Kim‐1‐TRFIA was used to detect the concentration of Kim‐1 in the serum of healthy controls and patients with AKI. Results The optimal coating antibody concentration and optimal Eu 3+ ‐labeled antibody dilution ratio for Kim‐1‐TRFIA are 1 μg/ml and 1:140, respectively. The linear range is 42.71–4666.69 pg/ml. The intra‐ and inter‐assay coefficients of variation are <10%. The specificity of our Kim‐1‐TRFIA is acceptable. The recovery is between 95.14% and 102.84%. The concentration of Kim‐1 in the serum of patients with AKI is 126.50 ± 67.99 pg/ml, which is significantly higher than that in the serum of healthy controls (49.72 ± 16.40 pg/ml, p < 0.001). Staging patients with AKI by glomerular filtration rate shows that the serum concentration of Kim‐1 increases significantly with increasing disease severity ( p < 0.05). Conclusion A highly sensitive Kim‐1‐TRFIA was established. With this immunoassay, a good differential diagnosis can be made, and healthy people and AKI patients can be differentiated by detecting the concentration of Kim‐1 in the serum. Moreover, the severity of AKI patients can be determined.

Development and application of an amplified luminescent proximity homogeneous assay-linked immunosorbent assay for the accurate quantification of kidney injury molecule-1

“…In addition, no cross-reactivity of other nephrotic biomarkers was observed. In previous studies, Kim-1-TRFIA showed a good correlation with Kim-1-ELISA ( Shaoxiong et al, 2022 ); in the present experiment, the results of Kim-1-TRFIA and Kim-AlphaLISA showed a good correlation ( R 2 = 0.9086). Thus, the developed method can be used to detect Kim-1 levels in serum and urine in clinical conditions and provide reliable, accurate, and stable results.…”

“…Shao ( Shao et al, 2014 ) et al estimated the diagnostic sensitivity and specificity of Kim-1 in AKI to be 74% and 86%, respectively. AKI is an increasingly frequent disease as part of acute kidney disease, defined clinically as a rapid loss of kidney function ( Liu et al, 2020 ; Shaoxiong et al, 2022 ), which can be fatal if not treated promptly ( Geng et al, 2021 ). AKI has been reported to be a common complication in hospitalized and critically ill patients ( Vijayan et al, 2021 ), and it can be induced by a variety of risk factors, such as sepsis, cirrhosis, acute pancreatitis, cancer, chronic kidney disease, COVID-19, and cardiac surgery ( Campbell et al, 2014 ; Gaffney and Sladen, 2015 ; Nassar and Qunibi, 2019 ; Gupta et al, 2021 ; Kuwabara et al, 2022 ; Wu et al, 2022 ).…”

“…The traditional method, ELISA, takes more than 3 h to detect Kim-1 and is not sufficiently sensitive ( Chaturvedi et al, 2009 ). Time-resolved fluorescence immunoassay for Kim-1 was recently developed; although the sensitivity has been greatly improved, the detection time remains long (2 h) ( Shaoxiong et al, 2022 ). Compared with TRFIA, AlphaLISA has the advantages of high sensitivity, high stability, time-saving, sample-saving, and easy operation.…”

“…In clinical practice, enzyme-linked immunosorbent assay (ELISA), fluorescence immunochromatography assay, and electrochemiluminescence immunoassay are commonly utilized to detect the concentration of Kim-1 in blood or urine ( Han et al, 2002 ; Chaturvedi et al, 2009 ; Vaidya et al, 2009 ; Zhang et al, 2013 ). In recent years, some novel detection techniques have been developed, such as time-resolved fluorescence immunoassay (TRFIA) based on double-antibody sandwich, to detect serum Kim-1 ( Shaoxiong et al, 2022 ). However, these techniques have limitations, such as insufficient sensitivity or time-consuming process.…”