Elsevier

Clinica Chimica Acta

Volume 452, 15 January 2016, Pages 32-37
Clinica Chimica Acta

Reference intervals of urinary acute kidney injury (AKI) markers [IGFBP7]∙[TIMP2] in apparently healthy subjects and chronic comorbid subjects without AKI

https://doi.org/10.1016/j.cca.2015.10.029Get rights and content
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Highlights

  • Reference ranges for the AKI risk biomarkers IGFBP7 and TIMP-2 are described.

  • We demonstrate that these markers are not elevated in chronic stable comorbid conditions.

  • The overall reference interval for [IGFBP7]∙[TIMP-2] in urine is 0.04–2.22 (ng/mL)2.

ABSTRACT

Background

Insulin-like growth factor-binding protein 7 (IGFBP7) and tissue inhibitor of metalloproteinases-2 (TIMP-2) have demonstrated significantly improved diagnostic performance in assessing risk for acute kidney injury (AKI) compared with existing biomarkers. We present the findings of a multi-site trial to determine the reference intervals for these biomarkers in apparently healthy adults and those with stable chronic morbid conditions without AKI.

Methods

A urine specimen was collected from apparently healthy subjects (N = 378) and subjects with at least one stable chronic morbidity (N = 372). Specimens were kept frozen until analysis with the NephroCheck® Test (Astute Medical). The test is comprised of fluorescence immunoassays for IGFBP7 and TIMP-2 and is used with the Astute140® Meter which quantifies the concentration of each biomarker. The meter multiplies the concentrations of IGFBP7 and TIMP-2 and displays the result as a numerical value ([IGFBP7]∙[TIMP-2]) expressed in (ng/ml)2/1000 which is called the AKIRisk™ Score.

Results

The reference intervals (inner 95%) for [IGFBP7]∙[TIMP-2] in all subjects (N = 750), apparently healthy subjects, and subjects with stable chronic morbidities were 0.04–2.22, 0.04–2.25, and 0.05–2.20 (ng/ml)2/1000 respectively. There was no statistical difference between reference intervals for apparently healthy and chronic stable morbid cohorts (p = 0.42).

Conclusions

Our investigation showed that urine [IGFBP7]∙[TIMP-2] values were not elevated in patients with stable chronic morbidities who did not have AKI.

Abbreviations

AKI
acute kidney injury
IGFBP7
insulin-like growth factor-binding protein 7;
KDIGO
kidney disease improving global outcomes
NGAL
neutrophil gelatinase-associated lipocalin
TIMP-2
tissue inhibitor of metalloproteinases-2

Keywords

Acute kidney injury
Cell-cycle arrest
Insulin-like growth factor-binding protein 7 (IGFBP7)
Nephrocheck
Reference interval
Tissue inhibitor of metalloproteinases-2 (TIMP-2)

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