Activating mutations in the epidermal growth factor receptor (EGFR) gene, particularly in the tyrosine kinase domain, occur in approximately 20% of non-small cell lung cancer (NSCLC) cases. These mutations, commonly found as deletions in exon 19 or the L858R mutation in exon 21, are crucial targets for EGFR tyrosine kinase inhibitors (TKIs). The third-generation EGFR TKI, osimertinib (TAGRISSO; AstraZeneca, UK), is effective against tumors with the T790M mutation and a liquid biopsy test has been approved by the US Food and Drug Administration as a companion diagnostic for TAGRISSO.This test is now widely implemented in various countries, including South Korea. To ensure high-quality testing, the Korean Association of External Quality Assessment Service launched a liquid biopsy EGFR proficiency testing program in 2017. This study analyzed the results of this program for 2017–2023. The number of participating laboratories increased from three in 2017 to 30 in 2023. All participating laboratories reported results using the Cobas z 480 analyzer (Roche Diagnostics, Germany). The accuracy of the test results was high with 100% correctness in several trials. However, errors were reported in some trials with false positives (e.g., detecting mutations in mutation-free samples) being more common than false negatives. This study evaluated Korean clinical laboratory performance when undertaking liquid biopsies for EGFR mutations. Continuous participation in the external quality assessment program helps laboratories maintain and improve the quality of liquid biopsy EGFR testing, ultimately benefiting patient care by ensuring accurate and reliable mutation detection.

Next-generation sequencing (NGS)-based liquid biopsy using peripheral blood offers a minimally invasive approach to detect tumor-derived circulating tumor DNA (ctDNA). Given the low abundance of ctDNA, accurate analysis is crucial, necessitating external quality assessments.Since 2020, the Korean Association of External Quality Assessment Service has conducted proficiency testing for NGS-based liquid biopsy. This study reviews the proficiency testing results from 2020 to 2023. The program was conducted biannually. Specimens were created by spiking fragmented DNA into fresh frozen plasma to simulate actual clinical samples. The number of target genes reported increased from 5 in 2020 to 17 in 2023. Results were assessed based on concordance with those obtained from targeted NGS panel testing performed before shipping the manufactured specimens.Participating laboratories used various NGS instruments and reagents. The read depth for each genetic variant varied across laboratories, while the reported read percentage of detected variants was generally consistent.Most laboratories accurately reported variants; however, some discrepancies related to variant position descriptions or incorrect reference sequence transcripts were noted. This study evaluates the performance of Korean clinical laboratories in NGS-based liquid biopsy. Continued vigilance in result reporting is necessary, and ongoing external quality assessments can enhance the reliability of NGS-based liquid biopsy testing.

Activating mutations in the epidermal growth factor receptor (EGFR) gene, particularly in the tyrosine kinase domain, occur in approximately 20% of non-small cell lung cancer (NSCLC) cases. These mutations, commonly found as deletions in exon 19 or the L858R mutation in exon 21, are crucial targets for EGFR tyrosine kinase inhibitors (TKIs). The third-generation EGFR TKI, osimertinib (TAGRISSO; AstraZeneca, UK), is effective against tumors with the T790M mutation and a liquid biopsy test has been approved by the US Food and Drug Administration as a companion diagnostic for TAGRISSO.This test is now widely implemented in various countries, including South Korea. To ensure high-quality testing, the Korean Association of External Quality Assessment Service launched a liquid biopsy EGFR proficiency testing program in 2017. This study analyzed the results of this program for 2017–2023. The number of participating laboratories increased from three in 2017 to 30 in 2023. All participating laboratories reported results using the Cobas z 480 analyzer (Roche Diagnostics, Germany). The accuracy of the test results was high with 100% correctness in several trials. However, errors were reported in some trials with false positives (e.g., detecting mutations in mutation-free samples) being more common than false negatives. This study evaluated Korean clinical laboratory performance when undertaking liquid biopsies for EGFR mutations. Continuous participation in the external quality assessment program helps laboratories maintain and improve the quality of liquid biopsy EGFR testing, ultimately benefiting patient care by ensuring accurate and reliable mutation detection.

Next-generation sequencing (NGS)-based liquid biopsy using peripheral blood offers a minimally invasive approach to detect tumor-derived circulating tumor DNA (ctDNA). Given the low abundance of ctDNA, accurate analysis is crucial, necessitating external quality assessments.Since 2020, the Korean Association of External Quality Assessment Service has conducted proficiency testing for NGS-based liquid biopsy. This study reviews the proficiency testing results from 2020 to 2023. The program was conducted biannually. Specimens were created by spiking fragmented DNA into fresh frozen plasma to simulate actual clinical samples. The number of target genes reported increased from 5 in 2020 to 17 in 2023. Results were assessed based on concordance with those obtained from targeted NGS panel testing performed before shipping the manufactured specimens.Participating laboratories used various NGS instruments and reagents. The read depth for each genetic variant varied across laboratories, while the reported read percentage of detected variants was generally consistent.Most laboratories accurately reported variants; however, some discrepancies related to variant position descriptions or incorrect reference sequence transcripts were noted. This study evaluates the performance of Korean clinical laboratories in NGS-based liquid biopsy. Continued vigilance in result reporting is necessary, and ongoing external quality assessments can enhance the reliability of NGS-based liquid biopsy testing.

Activating mutations in the epidermal growth factor receptor (EGFR) gene, particularly in the tyrosine kinase domain, occur in approximately 20% of non-small cell lung cancer (NSCLC) cases. These mutations, commonly found as deletions in exon 19 or the L858R mutation in exon 21, are crucial targets for EGFR tyrosine kinase inhibitors (TKIs). The third-generation EGFR TKI, osimertinib (TAGRISSO; AstraZeneca, UK), is effective against tumors with the T790M mutation and a liquid biopsy test has been approved by the US Food and Drug Administration as a companion diagnostic for TAGRISSO.This test is now widely implemented in various countries, including South Korea. To ensure high-quality testing, the Korean Association of External Quality Assessment Service launched a liquid biopsy EGFR proficiency testing program in 2017. This study analyzed the results of this program for 2017–2023. The number of participating laboratories increased from three in 2017 to 30 in 2023. All participating laboratories reported results using the Cobas z 480 analyzer (Roche Diagnostics, Germany). The accuracy of the test results was high with 100% correctness in several trials. However, errors were reported in some trials with false positives (e.g., detecting mutations in mutation-free samples) being more common than false negatives. This study evaluated Korean clinical laboratory performance when undertaking liquid biopsies for EGFR mutations. Continuous participation in the external quality assessment program helps laboratories maintain and improve the quality of liquid biopsy EGFR testing, ultimately benefiting patient care by ensuring accurate and reliable mutation detection.

Next-generation sequencing (NGS)-based liquid biopsy using peripheral blood offers a minimally invasive approach to detect tumor-derived circulating tumor DNA (ctDNA). Given the low abundance of ctDNA, accurate analysis is crucial, necessitating external quality assessments.Since 2020, the Korean Association of External Quality Assessment Service has conducted proficiency testing for NGS-based liquid biopsy. This study reviews the proficiency testing results from 2020 to 2023. The program was conducted biannually. Specimens were created by spiking fragmented DNA into fresh frozen plasma to simulate actual clinical samples. The number of target genes reported increased from 5 in 2020 to 17 in 2023. Results were assessed based on concordance with those obtained from targeted NGS panel testing performed before shipping the manufactured specimens.Participating laboratories used various NGS instruments and reagents. The read depth for each genetic variant varied across laboratories, while the reported read percentage of detected variants was generally consistent.Most laboratories accurately reported variants; however, some discrepancies related to variant position descriptions or incorrect reference sequence transcripts were noted. This study evaluates the performance of Korean clinical laboratories in NGS-based liquid biopsy. Continued vigilance in result reporting is necessary, and ongoing external quality assessments can enhance the reliability of NGS-based liquid biopsy testing.

Activating mutations in the epidermal growth factor receptor (EGFR) gene, particularly in the tyrosine kinase domain, occur in approximately 20% of non-small cell lung cancer (NSCLC) cases. These mutations, commonly found as deletions in exon 19 or the L858R mutation in exon 21, are crucial targets for EGFR tyrosine kinase inhibitors (TKIs). The third-generation EGFR TKI, osimertinib (TAGRISSO; AstraZeneca, UK), is effective against tumors with the T790M mutation and a liquid biopsy test has been approved by the US Food and Drug Administration as a companion diagnostic for TAGRISSO.This test is now widely implemented in various countries, including South Korea. To ensure high-quality testing, the Korean Association of External Quality Assessment Service launched a liquid biopsy EGFR proficiency testing program in 2017. This study analyzed the results of this program for 2017–2023. The number of participating laboratories increased from three in 2017 to 30 in 2023. All participating laboratories reported results using the Cobas z 480 analyzer (Roche Diagnostics, Germany). The accuracy of the test results was high with 100% correctness in several trials. However, errors were reported in some trials with false positives (e.g., detecting mutations in mutation-free samples) being more common than false negatives. This study evaluated Korean clinical laboratory performance when undertaking liquid biopsies for EGFR mutations. Continuous participation in the external quality assessment program helps laboratories maintain and improve the quality of liquid biopsy EGFR testing, ultimately benefiting patient care by ensuring accurate and reliable mutation detection.

Next-generation sequencing (NGS)-based liquid biopsy using peripheral blood offers a minimally invasive approach to detect tumor-derived circulating tumor DNA (ctDNA). Given the low abundance of ctDNA, accurate analysis is crucial, necessitating external quality assessments.Since 2020, the Korean Association of External Quality Assessment Service has conducted proficiency testing for NGS-based liquid biopsy. This study reviews the proficiency testing results from 2020 to 2023. The program was conducted biannually. Specimens were created by spiking fragmented DNA into fresh frozen plasma to simulate actual clinical samples. The number of target genes reported increased from 5 in 2020 to 17 in 2023. Results were assessed based on concordance with those obtained from targeted NGS panel testing performed before shipping the manufactured specimens.Participating laboratories used various NGS instruments and reagents. The read depth for each genetic variant varied across laboratories, while the reported read percentage of detected variants was generally consistent.Most laboratories accurately reported variants; however, some discrepancies related to variant position descriptions or incorrect reference sequence transcripts were noted. This study evaluates the performance of Korean clinical laboratories in NGS-based liquid biopsy. Continued vigilance in result reporting is necessary, and ongoing external quality assessments can enhance the reliability of NGS-based liquid biopsy testing.

Activating mutations in the epidermal growth factor receptor (EGFR) gene, particularly in the tyrosine kinase domain, occur in approximately 20% of non-small cell lung cancer (NSCLC) cases. These mutations, commonly found as deletions in exon 19 or the L858R mutation in exon 21, are crucial targets for EGFR tyrosine kinase inhibitors (TKIs). The third-generation EGFR TKI, osimertinib (TAGRISSO; AstraZeneca, UK), is effective against tumors with the T790M mutation and a liquid biopsy test has been approved by the US Food and Drug Administration as a companion diagnostic for TAGRISSO.This test is now widely implemented in various countries, including South Korea. To ensure high-quality testing, the Korean Association of External Quality Assessment Service launched a liquid biopsy EGFR proficiency testing program in 2017. This study analyzed the results of this program for 2017–2023. The number of participating laboratories increased from three in 2017 to 30 in 2023. All participating laboratories reported results using the Cobas z 480 analyzer (Roche Diagnostics, Germany). The accuracy of the test results was high with 100% correctness in several trials. However, errors were reported in some trials with false positives (e.g., detecting mutations in mutation-free samples) being more common than false negatives. This study evaluated Korean clinical laboratory performance when undertaking liquid biopsies for EGFR mutations. Continuous participation in the external quality assessment program helps laboratories maintain and improve the quality of liquid biopsy EGFR testing, ultimately benefiting patient care by ensuring accurate and reliable mutation detection.