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Update from the ACCLPP Laboratory Workgroup

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Presentation on theme: "Update from the ACCLPP Laboratory Workgroup"— Presentation transcript:

1 Update from the ACCLPP Laboratory Workgroup
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

2 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)

3 Recommended standards of practice for those using
point of care blood lead testing 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

4 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

5 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, revised practice standards

6 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

7 Guidelines 1a, 1b, 2, 3 and 4 Contamination 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

8 Guideline 5 Use of Capillary Blood from a Fingerstick
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

9 Guideline 6 Use of Venous Blood
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

10 Guidelines 7 through 111 Re-emphasize the manufacturer’s directions:
Storage requirements Operating requirements Power source considerations * Use of test kit components Instrument Calibration * based on use of POC analyzers in CDC field studies

11 Guideline 11 Analysis of Quality Control (QC) Materials
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

12 Guideline 13 Repeat Testing of the Original Specimen
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

13 Guideline 13 Repeat Testing of the Original Specimen
Guideline (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

14 Guideline 13 Repeat Testing of the Original Specimen
Guidance 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

15 Guideline 13 Confirmatory Testing
If blood lead ≥ 5 µg/dL the laboratory must refer for a confirmatory test either: the patient; or the venous blood specimen Guidance Level of 5 µg/dL selected to Maximize identification of children with levels ≥ reference value for blood lead

16 Guideline 14 Confirmatory Testing
Referring patient Preliminary results may be released with a comment initial test result is for screening purposes only confirmatory testing results are pending

17 Guideline 14 Confirmatory 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

18 Guideline 15 Reporting 5 – 10 µg/dL on Patient Reports
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

19 Guideline 16 Reporting Requirements
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

20 Guideline 17 Reporting Potential Contamination
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.

21 Guideline 18 Method Comparison
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

22 Guideline 19 Quality Assurance (external QA)
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).

23 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

24 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)

25 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

26 Thank You Questions?


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