Evaluation of a new measurement method of indoxyl sulfate in hemodialysis patients

Abstract

Indoxyl sulfate (IS) is related to the development of cardiovascular disease and total mortality in dialysis patients. High‐performance liquid chromatography (HPLC) is the conventional measurement approach. However, the HPLC method is difficult to perform in real time. Recently, the IS Assay Kit “NIPRO”, which enables the measuring of total IS by the enzyme method, was developed. This new reagent allows the easy and quick measurement of many samples using the automatic biochemical analyzer. Moreover, it was reported that it demonstrated satisfactory analytical performance. If this enzyme method is useful for measuring IS in hemodialysis, we can expect that the mechanism in which the IS effects adversely on a body as uremic toxins will be clarified. However, the enzyme method is more easily influenced by other coexisting substances. In this study, we have assessed on how the uremic toxins and anticoagulation effect on this new reagent and evaluate whether it can be put into practice effectively for hemodialysis patients. For the enzyme method, accuracy, simultaneous repeatability, linearity, limit of detection, influence of coexisting materials, and correlation with the HPLC method were examined. Accuracy and simultaneous repeatability were satisfactory, and linearity was good. The limit of detection was acceptable, and there was no influence of coexisting materials. With regard to the correlation, the regression equation was y = 0.947X + 7.987 and the correlation coefficient (r) was 0.972. This new reagent showed sufficient fundamental performance and had a good correlation with the conventional HPLC method for assessing the plasma of dialysis patients.

A pilot study comparing the efficiency of a novel asymmetric cellulose triacetate (ATA) dialyser membrane (Solacea‐190H) to a standard high flux polysulfone dialyser membrane (FX‐80) in the setting of extended hours haemodialysis

“…Additional plasma and serum samples were stored in a −80°C freezer for batched measurement of additional study factors by enzyme‐linked immunosorbent assays (ELISA), at the research laboratory within the Department of Nephrology at Monash Health. Samples were analysed as per the manufacturer's protocols for total, as opposed to free IS using the enzyme method (human kit supplied by Nipro Corporation, Osaka, Japan), as outlined in Abe et al 11 This study found the enzyme method for measuring total IS was accurate, repeatable and correlated well with HPLC measurements. Manufacturer's protocols were also applied for measurement of IL‐6 (AB46027, Abcam Australia), MDA‐LDL (10‐1143‐01, human oxidized LDL kit, Mercodia, Uppsala, Sweden) and α1M (Human Alpha‐1‐Microglobulin ELISA Kit AB22689 Abcam UK, for plasma; and Human alpha‐1 microglobulin ELISA Kit AB108884, Abcam UK, for dialysate).…”

Impact of Serum Indoxyl Sulfate on One-year Adverse Events in Chronic Kidney Disease Patients with Heart Failure

“…An enzymatic method was used to evaluate indoxyl sulfate concentrations in the current study. Although high-performance liquid chromatography is the gold standard, enzymatic methods have been reported to correlate well with high-performance liquid chromatography 14,15 . However, we could not exclude the influence of the indoxyl sulfate measurement method.…”

“…Indoxyl sulfate was measured using the enzyme method (NIPRO Corporation, Osaka, Japan) at the core laboratory of Okayama University, as previously described 14,15 . Briefly, sulfatase converted indoxyl sulfate to indoxyl.…”

Effect of dietary synbiotic supplementation on serum indoxyl sulfate in prevalent hemodialysis patients

“…Elevated IS levels in chronic kidney disease (CKD) are associated with hazardous effects like progression of CKD [3] cardiovascular disease (CVD) and all-cause mortality in HD patients [4].…”