Korean consensus guidelines, published in Annals of Laboratory Medicine on 8 October 2026, set out how to test circulating tumour DNA in pleural effusion and bronchoalveolar lavage fluid from patients with lung cancer. They were built from a targeted review of 27 studies, a national survey and a two-round Delphi panel of eight experts, modelled on existing blood-based ctDNA guidance.
The 15 recommendations cover three areas: pre-analytical handling of the specimen, analytical validation and quality management, and interpretation and reporting. The evidence was dominated by pleural effusion; lavage-specific data were sparse. In the survey, 23 of 109 respondents (21%) were already offering such testing, with lack of standard protocols, reimbursement and technical complexity cited as barriers.
For laboratories in India, where pleural fluid is often the first or only specimen in advanced lung cancer and tissue is limited, the framework is a useful starting point for validation. The recommendations are expert consensus on limited evidence, particularly for lavage, and do not replace tissue testing where tissue is available.
- Validate fluid-based ctDNA assays separately for pleural fluid and lavage before reporting
- Standardise collection volume, transport time and centrifugation for fluid specimens
- State the specimen type and its limitations clearly on the molecular report
- Recommend tissue or plasma testing when a fluid result is negative and suspicion remains
- Treat lavage-based results with more caution, as evidence is thinner
Why it matters
Fluid that is often discarded after cytology could deliver a targetable mutation result without another biopsy.
Don't overread it
These are consensus recommendations on limited evidence, especially for lavage; they do not establish equivalence with tissue testing.
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