Audit of estimated GFR and KDOQI Guidelines

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Audit of estimated GFR and K/DOQI Guidelines

• Sarah Knowles
• March 2006

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Audit response

• 10 labs returned questionnaires
• Questionnaire circulated to 18 labs
• Return rate 55
• Reason for poor returns - ? Not all labs
  considering using eGFR

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Q1 - Creatinine methods
March 2005 recommendations Within a renal
network, laboratories should provide comparable
creatinine results, ideally by the use of
identical methodology.
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• Q2 Do you report estimated GFR in Adults?
• Yes 4
• No 1
• In Process 5
• Guideline 4.
• Clinical Laboratories should report an estimation
  of GFR using a prediction equation in addition to
  reporting the serum creatinine measurement

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• Q3 What adult samples do you (or will you)
  report an eGFR on?
• All samples 6
• Only when eGFR requested 2
• On specific patient groups 1
• GP and OPD samples gt 18 yrs
• Undecided 1
• Guideline 4
• Clinical laboratories should report an
  estimation of GFR using a prediction equation in
  addition to reporting the serum creatinine
  measurement

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Q4 Do you report an estimated GFR in Children?

• Yes 0
• No 10
• Q5 - What age is used to define a child?
• lt 13 yrs 0
• lt 16 yrs 6
• lt 18 yrs 3
• 1 lab quoted 20 years as formula not valid below
  that
• MDRD publications state child is lt 18 yrs

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• Q7 What calculation do you use for determining
  eGFR in adults?
• MDRD 3
• Abbreviated MDRD 7
• Guideline 4 - The MDRD study and Cockcroft
  Gault equations provide useful estimates of GFR
  in adults.
• March 2005 update states 4 variable MDRD
  equation is preferable

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• Q10 Is eGFR available to all groups of
  requestors?
• Yes 8
• No - 1 x OPD and GP only
• - 1 x Not decided
• Q 12 At what level of eGFR do you report a
• gt result?
• eGFR gt 90 4
• eGFR gt 60 3
• Other 1 lab undecided probably gt 60
• 2 labs dont know at present
• March 2005 Recommendation When estimated GFR
  exceeds 90 ml/min/1.73m2 it should be reported as
  gt 90 ml/min/1.73m2

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• Q11 How do you report the eGFR?
• With the UE results 8
• As a single result 1
• Yet to decide 1
• March 2005 Recommendation All clinical
  biochemistry laboratories should report estimates
  of GFR alongside measurements of serum
  creatinine.
• Q9 Is the way that you report (or intend to
  report) eGFR Read-codeable?
• Yes 5
• No 4
• Dont know 1

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• Q13 Do you indicate what stage of
• Kidney disease to which the eGFR correlates?
• Yes 3
• No 6
• Other 1 lab refer to a website for more
  information
• Q14 Do you report the eGFR with the
  multiplication factor for Afro Caribbean
  patients?
• Yes 8
• No 2
• March 2005 recommendations Labs should
  communicate that the estimated GFR should be
  multiplied by 1.2 for Afro-Caribbean patients
  unless ethnic origin was available to the lab and
  correction already applied

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• Q15 What other interpretive information (if
  any) is supplied on the results report for eGFR?
• Website referral
• 2 labs Refer users to www.renal.org.uk if
  eGFR lt90
• 2 labs undecided Probably link to
  www.renal.org
• 2 labs link to a website for more information
• Coded Text
• 2 lab report with a coded text with limitations
  of eGFR and link to a website
• 1 lab report coded text with limitations of
  eGFR
• 1 lab no answer
• March 2005 recommendations laboratories should
  communicate that GFR estimates between 60 and 89
  ml/min/1.73m2 do not indicate CKD unless there is
  other laboratory or clinical evidence of disease

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• Q16 Have you agreed any referral guidelines
  with your local renal unit?
• No 3
• No answer 1
• 1 lab still in discussion
• Yes 5
• 1 x refer to renal association www.renal.org
• 3 x link to website
• 1 x eGFR lt 15 Immediate referral
• 15 29 Urgent referral
• 30 59 Routine referral
• Referral procedures are described in the CKD
  guidelines

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• Q17 - What test(s) do you offer for the
  detection of proteinuria?
• 2 labs - Spot ACR, Spot PCR,
• 24 hr Alb excretion, 24hr TP
• 7 labs - Spot ACR, Spot PCR and 24 hr TP
• 1 lab - Spot PCR and 24hr TP
• Guideline 5 It is not necessary to obtain a
  timed urine collection for detection and
  monitoring of proteinuria. Spot urine samples
  should be used in most cases.

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• Q18 Are there any selection criteria to
  determine which proteinuria assay is performed?
• No, all requests processed 10
• Yes 0
• Q19 If both Microalbumin and TP assays
  offered, what criteria (if any) are used to
  determine which assay performed?
• 4 x None whichever test requested
• 4 x Microalb result gt Analytical range
• 1 x Both UTP and Microalbumin on all requests.
  If UTP gt0.7g/L Microalbumin not performed
• 1 x No answer
• Samples should tested for albumincreatinine
  ratio or protein creatinine ratio depending on
  local practice

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• Conclusions
• eGFR availability and reporting
• Moving towards eGFR reporting
• Some discrepancies in reporting procedures and
  availability
• Most laboratories link to websites for further
  interpretation/ referral guidelines
• Proteinuria detection
• Labs offer 24 hour assays no longer
  recommended for CKD
• ACR or PCR? determined by requestor