Urine protein profiling with surface-enhanced laser-desorption/ionization time-of-flight mass spectrometry.

Author(s): Schaub S, Wilkins J, Weiler T, Sangster K, Rush D, Nickerson P

Publication: Kidney Int, 2004, Vol. 65, Page 323

PubMed ID: 14675066 PubMed Review Paper? No

Purpose of Paper

Conclusion of Paper

Studies

1. Study Purpose

   The purpose of this paper was to determine if the urine protein profile, as determined by surface-enhanced laser-desorption/ionization time-of-flight mass spectrometry (SELDI-TOF-MS), was influenced by analytical factors (matrix composition, instrument settings).

   Summary of Findings:

   Varying concentrations (20-100%) of matrix solutions resulted in a universal effect on observed peak number. Spot sampling protocol also influenced peak number in diluted and undiluted urine specimens.

   Biospecimens

   • Bodily Fluid - Urine

   Preservative Types

   • Frozen

   Diagnoses:

   • Not specified

   Platform:

   Analyte	Technology Platform
   Protein	SELDI-TOF MS

   Pre-analytical Factors:

   Classification	Pre-analytical Factor	Value(s)
   SELDI-TOF MS Specific	Reaction solution	20%, 35%, 50%, or 100% CHCA 20%, 35%, 50%, or 100% SPA
   Biospecimen Aliquots and Components	Aliquot size/volume	Undiluted urine Concentrated urine Diluted urine (1:2) Diluted urine (1:4) Diluted urine (1:8) Diluted urine (1:16)

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2. Study Purpose

   The purpose of this paper was to determine if the urine protein profile, as determined by surface-enhanced laser-desorption/ionization time-of-flight mass spectrometry (SELDI-TOF-MS), was influenced by patient (gender, blood in the urine, urine dilution), or acquisition related factors (sequential collection).

   Summary of Findings:

   First stream urine specimens collected from females only differed from mid-stream specimens in the 3-3.5 kD range. Storage of mid-stream urine specimens for 3 days at room temperature or 4 degrees C yielded little to no effect in terms of the number of peaks observed, while storage of first stream specimens resulted in new low molecular weight peaks. Five freeze thaw cycles resulted in a loss of peaks while 4 or less freeze thaw cycles did not significantly alter spectral profiles. The presence of blood in urine specimens resulted in the appearance of peaks consistent with serum proteins. Fluid loading of 4L per day affected the spectral profile while 2L per day had little effect.

   Biospecimens

   • Bodily Fluid - Urine

   Preservative Types

   • Frozen

   Diagnoses:

   • Normal

   Platform:

   Analyte	Technology Platform
   Protein	SELDI-TOF MS

   Pre-analytical Factors:

   Classification	Pre-analytical Factor	Value(s)
   Biospecimen Aliquots and Components	Aliquot sequential collection	First-void urine (the first 10-20 ml excreted) Mid-stream urine (the next 50-80 ml excreted)
   Preaquisition	Patient gender	Female Male
   Storage	Storage duration	Processing within 2 h of collection 3 days
   Storage	Storage temperature	4 degrees C Room temperature -70 degrees C
   Storage	Freeze/thaw cycling	1 freeze-thaw cycles 2 freeze-thaw cycles 3 freeze-thaw cycles 4 freeze-thaw cycles 5 freeze-thaw cycles
   Biospecimen Aliquots and Components	Blood and blood products	Presence of blood in urine specimen

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