Slides for taiwan Down's chat

1
UK NEQAS for PTH

• What are the causes of these significant
  between-method differences?
• Current methods for so called intact PTH
  actually measure PTH(7-84) as well as PTH(1-84).
• Most assays respond similarly to both but the
  DiaSorin Liaison assay shows only 50
  cross-reactivity with PTH(7-84).
• Calibration. Currently no universally accepted
  standard Although an International Standard is
  being assessed.
• Many other features of assay design Antibodies
  used, etc.

What can we do? In the short term, assay
adjustment may be the only option.
2
UK NEQAS for PTH - Reference Intervals
3
UK NEQAS for PTH - Reference Intervals
4
UK NEQAS for PTH - Reference Intervals
5
Scottish ACB PTH Project - Single patient study
Glasgow specimens

• Blood drawn from 106 patients attending renal
  clinic, Glasgow
• Aliquoted into six sets and frozen rapidly
• Assayed in Glasgow DiaSorin Liaison
• Distributed on dry ice to
• Edinburgh Abbott Architect Siemens Immulite
  2000
• Borders Beckman Access
• Dumfries Roche Elecsys
• Kirkcaldy Siemens ADVIA Centaur Data awaited
• Simple data analysis Overall mean of all
  results from all methods calculated
• Mean of results for each method expressed as
  percentage of overall mean

6
Scottish ACB PTH Project - Single patient study
Glasgow specimens Method mean concentration
expressed as percentage of overall mean
7
Scottish ACB PTH Project - Single patient study
Glasgow specimens

• Strategy for results harmonisation
• Take the Roche Elecsys as the baseline some
  evidence that it agrees with Nichols Allegro
  method used to establish K/DOQI guidelines.
• Use regression analysis to compare other methods
  with Roche Elecsys.

• Use these relationships to adjust either
• Each patients PTH concentration.
• The cut-off concentration used.