What are the most effective real-time markers of kidney cell damage?

NGAL, [TIMP‑2]·[IGFBP7], and KIM-1 are the most effective real-time markers of kidney cell damage, showing high diagnostic accuracy when measured at appropriate time windows and achieving superior performance when combined in multi-marker panels.

Abstract

Real‐time markers for kidney cell damage most consistently report high diagnostic accuracy when measured in the appropriate clinical context and time window. Urinary neutrophil gelatinase‐associated lipocalin (NGAL) rises within 2–6 hours after injury, with studies reporting area under the curve (AUC) values up to 0.91, sensitivities of 84–100%, and specificities as high as 99.5%. Urinary [TIMP‑2]·[IGFBP7] is typically measured at 6–12 hours post‐injury and shows AUC values ranging from 0.70 to 0.94, with reported sensitivities of 42–96% and specificities up to 95%. Urinary kidney injury molecule‑1 (KIM‑1) measured at 12–24 hours post‐insult yields moderate performance (AUC 0.66–0.84) with sensitivities between 75.9% and 91.6% and specificities up to 95.2%.

When combined in multi‐marker panels, these biomarkers often achieve superior performance. For example, panels including NGAL, [TIMP‑2]·[IGFBP7], and cystatin C have produced AUC values as high as 0.98, while combinations with additional markers have reached similar levels of discrimination. These findings, drawn from a diverse set of populations and clinical settings—ranging from cardiac surgery and intensive care to emergency presentations—support the use of NGAL, [TIMP‑2]·[IGFBP7], and KIM‑1 as effective real‐time indicators of kidney cell damage.

Methods

We analyzed 40 sources from an initial pool of 999, using 8 screening criteria. Each paper was reviewed for 5 key aspects that mattered most to the research question.

Papers identified with Elicit search

• n = 999

Papers screened using:

• Real-time Biomarker Detection

• Human Participants

• Diagnostic Performance Assessment

• Appropriate Study Design

• Comparative Assessment

• Clinical Study Setting

• Primary Research Quality

• Clinical Utility Assessment

• n = 999

Papers screened out

• n = 959

Papers included for extraction

• n = 40

Summary of Study Characteristics:

• Most commonly evaluated biomarkers:

  • Neutrophil gelatinase-associated lipocalin (NGAL): 29 studies
  • Kidney injury molecule-1 (KIM-1): 21 studies
  • [TIMP-2]·[IGFBP7]: 12 studies
  • Other biomarkers: each evaluated in 1–4 studies

• Study populations:

  • Critically ill: 7 studies
  • Cardiac surgery: 7 studies
  • Pediatric: 2 studies

• AKI definitions used:

  • KDIGO: 15 studies
  • AKIN: 8 studies

Individual Biomarker Performance

Combined Biomarker Performance

Several studies reported that combinations of biomarkers outperformed individual markers. Key findings from these studies include:

• Combinations of biomarkers showed improved AUC values exceeding individual markers, often above 0.9.

Timing of Detection and Clinical Context

Factors Affecting Biomarker Performance

• Patient population.
• Comorbidities.
• Timing of sampling.

Conclusion

The effectiveness of real-time kidney cell damage markers varies by clinical context, timing, comorbidities, and methodological factors, suggesting a need for standardization in future studies.

References

1. Ravi J. Desai, et al. (2022). Kidney Damage and Stress Biomarkers for Early Identification of Drug-Induced Kidney Injury: A Systematic Review.
2. W. Han, et al. (2008). Urinary biomarkers in the early diagnosis of acute kidney injury.
3. J. Koyner, et al. (2010). Urinary biomarkers in the clinical prognosis and early detection of acute kidney injury.

The information provided highlights the promising nature of these biomarkers in swiftly identifying kidney injuries and improving clinical outcomes.