ISO/TS 21310:2025

Overview

ISO/TS 21310:2025 - Traditional Chinese medicine - Microscopic examination of medicinal herbs is a Technical Specification from ISO/TC 249 that defines standardized methods for microscopic analysis of plant-derived medicinal herbs and decoction pieces used in traditional Chinese medicine (TCM). The document covers equipment, sampling, slide and powder preparation, mounting and swelling agents, observation procedures and test reporting. It applies to plant materials only (not animal or mineral materials) and updates the 2020 edition with revised sampling references and editorial improvements.

Key topics and technical requirements

• Scope and sampling
  • Sampling follows ISO 23723 (general requirements for herbal raw material and materia medica).
  • Representative samples should be preserved in airtight containers if needed.
• Apparatus
  • Optical microscope or slide scanner, optical/in-software micrometer, imaging devices (camera), slides and cover glasses, and botanical dissecting tools (tweezers, razor, microtome).
• Preparation methods
  • Cross- or longitudinal-section slides: soften, cut to typically 10–20 µm thickness, mount with mounting agent or chloral hydrate; paraffin embedding described when necessary.
  • Powder slides: about 1 mg sample, swollen with swelling agent/chloral hydrate for >10 min, smeared and mounted.
  • Mounting/swelling agents: examples include glycerine:water (1:1) or glycerine:95% ethanol:water (1:1:1); other suitable agents allowed.
• Fixation, maceration and sectioning
  • Fixatives: ethanol (50–70%), formalin (