Accurate Kidney Stone Analysis - Insights...2019/11/04  · Kidney Stone Analysis (KIDST) 1. Proper collection, handling, and labeling of kidney stones. i. Stone analysis collection

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Accurate Kidney Stone Analysis

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Presenter:

Paul J. Jannetto, PhDAssociate Professor of Laboratory Medicine and PathologyDirector, Clinical and Forensic Toxicology, Clinical Mass Spectrometry Lab and Metals Lab

Department of Laboratory Medicine and Pathology at Mayo Clinic, Rochester, Minnesota

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Disclosures• None

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Kidney Stones• Common worldwide (Prevalence 7-10% USA) • Increasing in frequency • Irretrievable specimen• Painful• Accurate analysis of kidney stones is important for the

management of patients

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Clinical Importance of Kidney Stone Analysis

• “After stone passage/removal, accurate stone analysis of urinary stone composition is the most crucial laboratory diagnostic procedure for the treatment and recurrence prevention in the stone-forming patient”

Siener R et al. Quality assessment of urinary stone analysis: results of a multicenter study of laboratories in Europe. PLoS One 2016;11(6):e0156606 PMID: 27248840

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Kidney Stone Analysis (KIDST)1. Proper collection, handling, and labeling of kidney stones.

i. Stone analysis collection kit available (T550)ii. Clean any blood or foreign material from the stone with wateriii. Dry stone at room temperature (~24 hrs) on a tissue/towel and

send entire stone in screw-capped plastic container.iv. Indicate source of stone (e.g. urine, kidney, ureter, bladder, etc.)

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The Kidney Stone Must Be Clean and Dry for Accurate Analysis

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Kidney Stone Analysis (KIDST)• Stone analysis should be done with modern methods, either

infrared spectroscopy or X-ray diffraction. • Fourier transform infrared (FTIR) spectroscopy is considered the

reference method.

Gambaro G. et al. Metabolic diagnosis and medical prevention of calcium nephrolithiasis and its systemic manifestations: a consensus statement. J Nephrol 2016;29:715-734.

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FTIR Analysis

Clean/dry kidney stoneCrush

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Example of Calcium Oxalate Monohydrate

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Importance of a “Dry Stone”

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Common Types of Kidney Stones% Composition

Calcium oxalateHydroxyapatiteUric acid (any)Struvite (any)Brushite (any)

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What should your lab do if you received a wet or dirty stone from the patient?

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