Work Item
ASTM WK64471

New Test Method for Assessment of Fungal Biomass on Surfaces or Coatings by Measuring Fungal -N-Acetylhexosaminidase (NAHA) Activity

1. Scope

1.1 This test method contains procedures for both collection and analysis of surface swab samples for total fungal biomass by measuring the activity of fungal -N-acetylhexosaminidase (NAHA) by use of a 4-methylumbelliferyl-labelled fluorogenic enzyme substrate together with an inhibitor of non-fungal NAHA activity. 1.2 NAHA activity is present in all forms of fungal material such as spores, hyphal fragments, and other particles of fungal origin that are not optically recognizable. Collectively, this material is the fungal biomass. 1.3 This test method does not identify or differentiate fungal taxa. 1.4 This test method does not differentiate between viable and non-viable fungi. 1.5 This test method can differentiate surface fungal biomass loading. 1.5.1 This test method can be used to assist the visual assessment in categorizing fungal loading on clean, dirty, and contaminated surfaces. 1.5.2 This test method does not measure bacteria. 1.6 Units--The values stated in SI units are to be regarded as the standard. The values given in parentheses after SI units are provided for information only and are not considered standard. For purposes of this standard, these terms have no technical meaning. 1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 1.8 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.


fungal growth; fungal biomass; building materials; microbiological assay; mold; enzyme activity; -N-acetylhexosaminidase; NAHA; fluorometer; fluorescent count


This is an objective quantitative method for measuring total fungal biomass on surfaces and has a high reproducibility.

The title and scope are in draft form and are under development within this ASTM Committee.


Developed by Subcommittee: D22.08

Committee: D22

Staff Manager: Ashley Wiand

Work Item Status

Date Initiated: 07-20-2018

Technical Contact: Michael Kaniuga

Item: 001

Ballot: D22.08 (20-01)

Status: Will Reballot Item

Item: 003

Ballot: D22.08 (20-02)

Status: Will Reballot Item

Item: 002

Ballot: D22.08 (21-01)

Status: Will Reballot Item

Item: 017

Ballot: D22 (23-03)

Status: Negative Votes Need Resolution