Clinical and Laboratory Standards Institute C40—Measurement Procedures for the Determination of Lead in Whole Blood is intended for use by members of the medical laboratory community involved in the determination of lead (Pb) in blood, as well as by personnel involved in specimen collection. This guideline discusses the clinical significance of blood lead (BPb) measurements; specimen collection; and Pb determination by graphite furnace atomic absorption spectrometry, anodic stripping voltammetry (based on disposable screen-printed electrode technologies), and inductively coupled plasma mass spectrometry. It also discusses reference materials, QC procedures, and laboratory policies for BPb testing.

This guideline replaces CLSI C40-A2, published in 2013. Several changes were made in this edition, including: 

• Adding detailed analytical procedures for BPb measurements based on inductively coupled plasma mass spectrometry 

• Updating: 

– Information on the clinical and public health significance of BLLs < 5 µg/dL (0.24 µmol/L) 

– Guidance on anodic stripping voltammetry (ASV) devices that use disposable screen-printed electrode technologies 

– Guidance for laboratories on quality assurance practices at BLLs of 3.5 µg/dL 

– Current information on laboratory certification and proficiency testing programs (or external quality assessment) in the United States, Canada, and Europe, provided in Appendix A 

– The protocol for checking materials and specimen collection supplies for Pb contamination, provided in Appendix B 

• Deleting: 

– The classic ASV procedure for older benchtop instrumentation 

– A procedure for urine Pb measurement, which is now considered redundant for clinical purposes

The goal of this guideline is to provide up-to-date information on the determination of lead (Pb) in whole blood (BPb). Preexamination considerations, such as specimen collection for screening and diagnosis, the role of capillary compared with venous blood specimens, anticoagulant selection, collection containers, and contamination monitoring and control, are included. 

Examination considerations are focused on the three major instrumental methods used to determine BPb: (1) electrothermal atomic absorption spectrometry (ETAAS), also known as graphite furnace atomic absorption spectrometry (GFAAS); (2) inductively coupled plasma mass spectrometry (ICP-MS); and (3) anodic stripping voltammetry (ASV) based on disposable electrochemical technologies. CLSI C40 does not include considerations for classic ASV based on benchtop devices that use a carbon-based electrode with a thin film of mercury (Hg) because commercial instrumentation is no longer available and analytical performance is no longer considered fit for purpose. Other considerations include internal and external QA and QC and guidance on troubleshooting common problems with BPb testing. 

Postexamination considerations, such as criteria for repeat testing of the original clinical specimen, reporting test results, and guidance on requesting an additional blood specimen, are also included. Information on proficiency testing (PT) programs is provided, along with guidance on acceptable performance across the various schemes. 

CLSI C40 also provides a brief review of the background and clinical significance of BPb measurements, as well as recommendations for evaluating test results within the context of method uncertainty, contamination errors, and other laboratory limitations. 

This guideline is intended for use by members of the medical laboratory community worldwide (and by point-of-care [POC] testing facilities) involved in the measurement of BPb using well-established methods, as well as by personnel involved in specimen collection. The determination of Pb in urine is no longer included because this test is now considered redundant for clinical purposes.