Patrick J. Parsons, PhD Chief, Laboratory of Inorganic and Nuclear Chemistry Wadsworth Center, New York State Dept of Health, Albany, NY Chair Laboratory Workgroup (LWG) Advisory Committee on Childhood Lead Poisoning Prevention (ACCLPP) July 25, 2013 Update from the ACCLPP Laboratory Workgroup
26
Embed
Patrick J. Parsons, PhD Chief, Laboratory of Inorganic and Nuclear Chemistry Wadsworth Center, New York State Dept of Health, Albany, NY Chair Laboratory.
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
Patrick J. Parsons, PhD
Chief, Laboratory of Inorganic and Nuclear ChemistryWadsworth Center, New York State Dept of Health, Albany, NY
Chair
Laboratory Workgroup (LWG)Advisory Committee on Childhood Lead Poisoning Prevention (ACCLPP)
July 25, 2013
Update from the ACCLPP Laboratory Workgroup
Laboratory Workgroup Membership
Chair Patrick J. Parsons, PhD, FRSC (NYS DOH)
Members Valerie Charlton, MD, MPH (CA DOH / CLPPB)Leland McClure, PhD, D-ABFT (Quest
Diagnostics)Megan Sandel, MD, MPH (Boston Medical
Center) Donald Simmons, PhD (UIHL)Noel Stanton, MS (WSLH)
CDC SMEs Walter Alarcon, MSc, PhD (CDC / NIOSH)Mary Jean Brown, ScD, RN (CDC / NCEH)Jeffery M. Jarrett, MS (CDC / NCEH)Robert L. Jones, PhD (CDC / NCEH)
Patrick J. Parsons, PhD
Chief, Laboratory of Inorganic and Nuclear ChemistryWadsworth Center, New York State Dept of Health, Albany, NY
Chair
Laboratory Workgroup (LWG)Advisory Committee on Childhood Lead Poisoning Prevention (ACCLPP)
July 25, 2013
Recommended standards of practice for those using
point of care blood lead testing
Charge #2 to Laboratory Workgroup
The WG should address the need for recommended standards of practice for those using point of care blood lead testing.
* ACCLPP, October 2009
Laboratory Workgroup Meetings
Web Conferences / Conference Calls February 7, 2011 April 8, 2011 June 13, 2011 August 24, 2011 September 27, 2011
Finalized questions for Magellan Biosciences October 17, 2011
Q/A with Magellan Biosciences November 23, 2011 October 1, 2012 - revised practice standards
Guidance
Based on the New York State Department of Health’s Clinical Laboratory Evaluation Program Blood Lead Practice Standards for Screening Tests Only
Divided into Statements of Guidelines Guidance in Interpretation
Guidelines 1a, 1b, 2, 3 and 4Contamination Control
Work area (1a, 1b)-Universal Precautions
Contamination Control in the Work Area
Materials and Specimen collection Preparing the skin collection site prior to capillary skin
puncture
Sample Processing
Guideline 5Use of Capillary Blood from a
Fingerstick
Guideline Ensure no air gaps present in the capillary
Guidance Appropriate for screening purposes only Typically used with a POC device Consult the manufacturer’s directions
Guideline 6Use of Venous Blood
Guideline Ensure the quality of the blood specimen
Guidance Preferred for blood lead testing purposes Use only EDTA or heparin as anticoagulants Other issues: Fill volume, mixing prior to
aliquoting, and monitoring for blood clots
Blood specimens with visible clots should be rejected
Guidelines 7 through 111
Re-emphasize the manufacturer’s directions:
6) Storage requirements7) Operating requirements8) Power source considerations *9) Use of test kit components10) Instrument Calibration
* based on use of POC analyzers in CDC field studies
Guideline 11Analysis of Quality Control (QC)
Materials
Guideline Ideally
Two clinically significant levels each analytical run At a minimum
Two clinically significant levels• Each new test kit lot• Each new shipment• Each new operator (two weeks)• When problems are suspected or identified
Guidance Frequency of QC should reflect volume of
testing
Guideline 13Repeat Testing of the Original
SpecimenGuideline If initial result ≥ 5 µg/dL (at or above the
current Reference Value), reanalyze (if volume permits) Original specimen Purpose is to rule out possible contamination error
Guidance If insufficient volume, e.g. capillary specimen,
report initial result and refer patient for confirmatory testing
Guideline 13Repeat Testing of the Original
SpecimenGuideline (continued) Resolve large discrepancies, if possible
EITHER additional analysis
OR report test results as inconclusive, with comment• insufficient specimen to repeat the analysis• refer patient for confirmatory testing
Guideline 13Repeat Testing of the Original
SpecimenGuidance Acceptable differences in repeats
5 to 20 µg/dL 3 µg/dL 21 to 40 µg/dL 4 µg/dL over 40 µg/dL 10%
Discard outliers Report average of two remaining values Refer patient for confirmatory testing
For any result exceeding 5 µg/dL if there is any uncertainty in the validity of the test
Guideline 13Confirmatory Testing
Guideline If blood lead ≥ 5 µg/dL the laboratory
must refer for a confirmatory test either:
a. the patient; orb.the venous blood specimen
Guidance Level of 5 µg/dL selected to
Maximize identification of children with levels ≥ reference value for blood lead
Guideline 14Confirmatory Testing
Referring patient
Preliminary results may be released with a comment initial test result is for screening purposes only confirmatory testing results are pending
Guideline 14Confirmatory Testing
Referring venous blood
Confirmatory testing by CLIA-certified laboratory Method categorized by CLIA as high complexity
Preliminary results may be released with a comment that results of confirmatory testing are pending
Unopened venous specimen is preferable
Guideline 15Reporting 5 – 10 µg/dL on Patient
ReportsGuideline Reference ranges must indicate that BLLs 5-
9 mg/dL have been associated with adverse health effects in children aged 6 years and younger
Guidance Reports should not indicate that
BLLs < 10 µg/dL are “normal”
This Guideline is now redundant given the change in definition of elevated and should be deleted
Guideline 16Reporting Requirements
Guideline Report all blood lead results to the proper
state or federal agency.
Guidance Essential
for proper follow-up for public health surveillance
Variations by state Data, timeframes, and mechanisms
Guideline 17Reporting Potential Contamination
Guideline Indicate possible false positive when
specimen is received in a container not known to be lead-free
Guidance No need to footnote in report for containers
cleared through in-house lot-testing.
Guideline 18Method Comparison
Guideline Periodically compare POC BLLs with
confirmations
Guidance Acceptable differences
5 to 20 µg/dL 3 µg/dL 21 to 40 µg/dL 4 µg/dL over 40 µg/dL 10%
Periodically review personnel competency reviews performance of quality control and proficiency testing
Guideline 19Quality Assurance (external QA)
Guideline Participation in proficiency testing provides
valuable assessment of analytical performance
Guidance no federal requirement for CLIA waived *
but highly recommended
*Some states do require regular participation in proficiency testing to receive reimbursement for test costs (e.g. CA, WI).
Other issues under consideration by the Lab Workgroup
Charge #3 Alternate matrices for assessing lead exposure
The WG should investigate and report to the ACCLPP on the efficacy, reliability and validity of measuring lead in saliva as an index of lead exposure. To a lesser extent, the WG should investigate report to the ACCLPP on the reliability and validity of measuring lead in other non traditional matrices such as sweat, hair, nails and packed red cells as indices of lead exposure
Other issues under consideration by the Lab Workgroup
Charge #4 Environmental lead analytical issues
The WG should investigate and report to the ACCLPP on the reliability of current technologies for assessing the lead content of paint, plastics and other environmental samples, laboratory capacity and capability for handling
Examples:• Hand held XRF use for assessing Pb in consumer products• Use of area concentrations (µg/cm2) versus mass fractions
(ppm or mg/kg)
Other issues under consideration by the Lab Workgroup
Charge #5 Reference intervals for adult lead exposure
The WG should investigate and report to the ACCLPP on how clinical laboratories should report the reference interval for adult lead exposure. Currently, many labs report <30 µg/dL, <20 µg/dL as “normal” for adult blood lead levels