CEI LABS, Inc.
Laboratory Excellence Since 1987

Microbiology Department

Analytical Methods

  1. NONVIABLE AIRBORNE: Spore Traps, Air-O-Cell, Allergenco-D
  2. NONVIABLE SURFACE: Tape Lift, Swabs, Bulk
  3. VIABLE BULK: Bulk, Dust
  4. VIABLE AIRBORNE: Andersen Sampler, Impactor
  5. DUST CHARACTERIZATION

1. NONVIABLE AIRBORNE: Spore Traps, Air-O-Cell, Allergenco-DMenu

The cassette slide is mounted on a slide and examined by direct microscopy at 40x to 60x magnification. Mold spores, pollen, and mycelial fragments are identified to genus level and quantified by counting 28 grid columns. A qualitative “debris rating” is assigned for each non-microbial component. If a spore count reaches 100 before analyzing the entire slide, then quantification is extrapolated. Laboratory results are reported as spores per cubic meter (m3) of sample volume

Interpreting Test Results:

  • Environmental Category: Predominately Outside, Outside/Inside, or Water Damage.
  • Debris Rating: Low = 0% to 25% ; Moderate = 26% to 50%; Heavy = 50%.

Advantages:

  • Fast turn around time
  • Provides quantification data
  • May identify molds that are not visible

Disadvantages:

  • Spores can be difficult to identify to genus level
  • Does not differentiate between viable and nonviable spores
  • Aspergillus and Penicillium are reported together
  • High concentrations of spores are difficult to count

2. NONVIABLE SURFACE: Tape Lift, Swabs, BulkMenu

The tape lift is mounted on a slide and examined by direct microscopy at a resolution of 40x to 60x magnification. Mold spores are identified to genus level and a qualitative rating assigned based on visual estimates. Laboratory results are reported as a qualitative rating for each mold genus identified.

Interpreting Test Results:

Trace = few spores no active growth; Few = < 1% spores no active growth; Many = 1% to 10% spores active growth; Numerous = 10% to 50% spores active growth; Massive = 50% spores active growth.

* Note: Swab and Bulk samples require transfer of mold spores to a tape lift before examination

Advantages:

  • Fast turn around time
  • Provides qualitative data

Disadvantages:

  • Does not provided quantitative data
  • Does not differentiate between viable and nonviable spores
  • Spores can be difficult to identify to genus level

3. VIABLE BULK: Bulk, DustMenu

The sample is weighed, suspended in solution, plated in a culture dish, and placed in an incubator at 25° Celsius. It usually takes 5 to 10 days time in the incubator to allow for sufficient growth of mold colonies. After the incubation period a representative sample is collected via tape lift, mounted on a slide, and analyzed using a biological microscope at a resolution of 40x to 60x. Mold colonies are identified to the genus, or species level, and quantified. Laboratory results are reported in colony forming units (CFU) per gram of sample material.

Advantages:

  • Provides identification and quantification data
  • More accurate identification method than non-viable testing
  • Identifies viable mold present

Disadvantages:

  • Requires longer turn around times
  • Not effective on porous surfaces
  • Not all spores may culture which can distort results

4. VIABLE AIRBORNE: Andersen Sampler, ImpactorMenu

The culture plate is placed in an incubator at 25° Celsius for 7 to 10 days to allow for growth of mold colonies. After incubation, a representative sample is collected via tape lift, mounted on a slide, and analyzed using a biological microscope at a resolution of 40x to 60x. Mold colonies identified to the genus, or species level, and quantified. Laboratory results are reported as colony forming units (CFU) per cubic meter (c3) of sample volume.

Advantages:

  • Provides identification and quantification
  • More accurate identification method than non-viable testing

Disadvantages:

  • Longer turn around time
  • Does not identify nonviable spores
  • Not all spores may culture which can distort results

5. DUST CHARACTERIZATIONMenu

The sample is placed on a slide and two plates prepared; one plate using lactophenol-cotton blue and the second plate with a refractive index liquid. The two plates are then analyzed using a PLM microscope at 100x to 400x magnification. Dust components are identified based on optical properties and qualitatively reported including: skin scales, mold, animal allergens, fibers, ashes, and building materials, and food matter. Laboratory results are reported as a relative percentage (%) for each identified dust component.

Advantages:

  • Inexpensive test method
  • Identifies major dust components

Disadvantage:

  • Does not provide chemistry data