PTH ASSAY A PROBLEM AND A SOLUTION

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PTH ASSAY- A PROBLEM AND A SOLUTION

• DR.SIMON WALKER(Scottish Biochemists Network),
  ANDY ELLIS (on behalf of UKNEQAS),
• DR.ALISON ALMOND(Scottish Renal Registry)

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PO4
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.....THE PROBLEM

• 7 DIFFERENT ANALYSERS ACROSS SCOTLAND BUT ALL
  USING SAME METHOD

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.....THE PROBLEM

• 7 DIFFERENT ANALYSERS ACROSS SCOTLAND BUT ALL
  USING SAME METHOD
• WIDE VARIATION IN HOW REFERENCE RANGES
  ESTABLISHED- BUT, REFERENCE RANGES ALL SIMILAR

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.....THE PROBLEM

• 7 DIFFERENT ANALYSERS ACROSS SCOTLAND BUT ALL
  USING SAME METHOD
• WIDE VARIATION IN HOW REFERENCE RANGES
  ESTABLISHED- BUT, REFERENCE RANGES ALL SIMILAR
• EXTERNAL QUALITY ASSESSMENT DATA SHOW lt3.5
  VARIABILITY ACROSS WORKING RANGE

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......THE SOLUTION.

• ADOPT A SINGLE REFERENCE RANGE FOR P04
  ACROSS SCOTLAND.

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Corrected Calcium
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.....THE PROBLEM
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.....THE PROBLEM

• 6 different analysers using 2 different
  techniques for total calcium

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.....THE PROBLEM

• 6 different analysers using 2 different
  techniques for total calcium
• 3 different reference ranges for total calcium

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.....THE PROBLEM

• 6 different analysers using 2 different
  techniques
• 3 different reference ranges
• 2 different techniques for albumin measurements

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.....THE PROBLEM

• 6 different analysers using 2 different
  techniques
• 3 different reference ranges
• 2 different techniques for albumin measurements
• Reference ranges for albumin vary

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.....THE PROBLEM

• 6 different analysers using 2 different
  techniques
• 3 different reference ranges
• 2 different techniques for albumin measurements
• Reference ranges for albumin vary
• Lowest albumin reported varies 1g/L-10g/L

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........THE REAL HEADACHE
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........THE REAL HEADACHE

• 4 labs.do not adjust for albumin

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........THE REAL HEADACHE

• 4 labs.do not adjust for albumin
• 4 report only total Ca, 4 report only adjusted
  Ca, 8 report both

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........THE REAL HEADACHE

• 4 labs.do not adjust for albumin
• 4 report only total Ca, 4 report only adjusted
  Ca, 8 report both
• 7 DIFFERENT ADJUSTMENT FORMULAE!

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....ROUGHLY TRANSLATED..

• ALBUMIN CALCIUM

• RANGE OF CORRECTED Ca

• 48 2.24
• 30 2.3
• 25 2.44
• 40 2.58

• 1.99 2.20
• 2.43 - 2.64
• 2.65 2.86
• 2.53 2.7

IN 40 60 OF CASES VARIATION IN cCa CAUSED
BY DIFFERENT FORMULAE WOULD HAVE AFFECTED
CLINICAL DECISIONS

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.......THE SOLUTION.

• All labs. will report a corrected calcium, but
  the correction will only apply if albumin is
  gt25g/L.
• One correction factor will be used universally,
  40/0.02.

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PARATHYROID HORMONE
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ONE PATIENT 5 LABORATORIES
DiaSorin Liaison (GRI)
Beckman Access (BORDERS)
Roche Elecsys (DGRI)
Siemens Centaur (KIRKCALDY)
Siemens Immulite (RIE)
PARATHYROID HORMONE LEVEL (pmol/L
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ONE PATIENT 5 LABORATORIES
DiaSorin Liaison (GRI)
3.4 FOLD DIFFERENCE
Beckman Access (BORDERS)
Roche Elecsys (DGRI)
Siemens Centaur (KIRKCALDY)
Siemens Immulite (RIE)
PARATHYROID HORMONE LEVEL (pmol/L
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IN EACH OF THE 17 OTHER PATIENTS.....
1.4 -4.2 FOLD DIFFERENCE
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PTH ASSAYS USED IN SCOTLAND

• ASSAY

• SIEMENS IMMULITE (RIE)
• SIEMENS CENTAUR (KIRKCALDY)
• ROCHE ELECSYS (DGRI)
• DIASORIN LIAISON (GRI)
• BECKMANS ACCESS (BORDERS)

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PTH ASSAYS USED IN SCOTLAND

• ASSAY

• NORMAL RANGE

• SIEMENS IMMULITE (RIE)
• SIEMENS CENTAUR (KIRKCALDY)
• ROCHE ELECSYS (DGRI)
• DIASORIN LIAISON (GRI)
• BECKMANS ACCESS (BORDERS)

• 1.2 -7.6 pmol/L
• 1.2 - 7.6 pmol/L
• 1.6 - 6.9 pmol/L
• 1.0 6.5 pmol/L
• 1.2 7.6 pmol/L

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THE PLAN FOR SRR BONE AUDIT

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THE PLAN FOR SRR BONE AUDIT

• THE RENAL UNITS

• START APRIL 2009
• BIANNUAL APRIL/NOVEMBER
• PRE-DIALYSIS BLOODS AFTER SHORT ID GAP
• TOURNIQUET REMOVED BEFORE WITHDRAWING BLD.
• CALCIUM/PHOSPHATE/ ALBUMIN in SERUM GEL TUBE
• EDTA PLASMA FOR PTH

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THE PLAN FOR SRR BONE AUDIT

• THE LABORATORIES

• THE RENAL UNITS

• CORRECTED CALCIUM REPORTED BY ALL LABS.IF
  ALBUMIN gt25g/L
• 40/0.02 CORRECTION APPLIED IN ALL LABS.
• PTH WILL BE REPORTED IN pmol/L BY ALL LABS.
• NEW ASSAY SPECIFIC PTH REFERENCES WILL BE
  APPLIED (NOVEMBER 2009)

• START APRIL 2009
• BIANNUAL APRIL/NOVEMBER
• PRE-DIALYSIS BLOODS AFTER SHORT ID GAP
• TOURNIQUET REMOVED BEFORE WITHDRAWING BLD.
• CALCIUM/PHOSPHATE/ ALBUMIN in SERUM GEL TUBE
• EDTA PLASMA FOR PTH

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THANKS TO - SIMON WALKER ANDY ELLIS KAREN
SMITH SUE ROBERTSON KEN DONALDSON PROF.ISLES
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