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Kidney Week

Abstract: FR-PO1078

Point-of-Care Urinary Neutrophil Gelatinase-Associated Lipocalin Readings Are Highly Predictive of Formal Laboratory Levels

Session Information

Category: Pediatric Nephrology

  • 1700 Pediatric Nephrology

Authors

  • Woollen, Hailey E., Center for Acute Care Nephrology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, United States
  • Krallman, Kelli A., Center for Acute Care Nephrology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, United States
  • Goldstein, Stuart, Center for Acute Care Nephrology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, United States
Background

Since the discovery and validation of urinary neutrophil gelatinase-associated lipocalin (NGAL) as an early, non-invasive marker of kidney injury, clinicians are able to more rapidly, and reliably, predict the development of acute kidney injury (AKI.) Urinary NGAL has been validated on various clinical lab platforms, but has yet to be assessed using point of care (POC) techniques. A reliable POC urinary NGAL test would offer a rapid and inexpensive screening test for AKI that could be clinically valuable in both inpatient and outpatient settings.

Methods

Hospitalized patients from 2 different pediatric hospitals who were exposed to 3 or more nephrotoxic medications simultaneously or 3 or more consecutive days of either IV vancomycin or an IV aminoglycoside had a daily urine collection for 7 consecutive days. Discrete laboratory urinary NGAL results were obtained using The NGAL Test™ (Bioporto, Denmark) and stratified corresponding to a colorimetric NGAL test (Bioporto) with ranges of: 25ng/mL, 50ng/mL, 100ng/mL, 150ng/mL, 300ng/mL and 600ng/mL. Different urinary NGAL cutoffs were then used to determine sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV), with the laboratory NGAL Test™ serving as the reference standard.

Results

In total, 86 individual patients (55% male, median age 13.2 years, range 4 months to 34 years) had 521 paired laboratory and POC urinary NGAL assessment. Of the 521 urine samples, 94 were analyzed using fresh urine and 427 using frozen urine samples. The POC performance data are depicted in the table.

Conclusion

A POC urinary NGAL assessment of <300ng/mL was highly predictive of an NGAL Test™ value <300ng/mL. We suggest this colorimetric POC assay is useful as a surrogate to the laboratory NGAL Test™ and to rule out risk for AKI. Patients with a POC test >300 ng/ml should have a confirmatory NGAL Test™ assessed.

Results
NGAL Test™ thresholdSensitivitySpecificityPositive Predictive ValueNegative Predictive Value
<50ng/mL93.90%
(89.01-97.04%)
66.11%
(60.94-71.01%)
56.00%
(52.28-59.66%)
95.93%
(92.8-97.74%)
<150ng/mL97.14%
(85.08-99.93%)
81.48%
(77.74-84.84%)
27.42%
(23.71-31.46%)
99.75%
(98.29-99.96%)
<300ng/mL100.00%
(85.75-100%)
89.34%
(86.28-91.91%)
31.17%
(25.99-36.87%)
100.00%

Sensitivity, specificity, PPV, NPV (95% confidence intervals)