FAQ’S
What types of samples are suitable for use with InTray™ DM?
The system is designed to culture hair, skin or nail samples. Hair samples should be grasped at the uninfected end and several small pieces should be cut from the infected portion for inoculation onto the surface of the medium. Nail samples should be cut into several small pieces for best results.
What is the optimum microscope setting to be used for fungus identification?
Based on observations, 100x magnification is used to determine general growth characteristics without opening the tray window. Clarification of the micro and macroconidia should use a higher power such as 200x magnification. Be sure to focus up and down through the medium. Some organisms will grow on top of and through the medium. The colony growth will exhibit characteristic color and structures (See InTray™ Dermatophyte Identification Chart).
How soon will I observe a color change in the DM medium?
Color change can be observed as early as 24 hours. This is highly dependent upon the species and the sample. Observe the tray for a color change for 10 days before discarding it. Colony growth must also be observed.
Will bacteria and other saprophytic fungi grow on the InTray™ DM?
Bacteria are inhibited from growing. Some saprophytic fungi grow on the medium and they will produce a red color change. However the colonies are darker in color (brown, green or black). Aspergillus and Penicillium are the most common.
Will yeast grow on the InTray™ DM?
Most Candida species are inhibited except Candida albicans. C. albicans will cause a rapid (24-48 hours) color change. Other yeast species take 7 or more days to grow. Prolonged growth will change the color slowly to red. However, the appearance of yeast colonies is pasty, waxy or shiny (glass-like) unlike the cottony or granular dermatophyte growth. Yeast and saprophytic fungi can be pathogenic depending upon the patient’s general health and medications.
Why did the InTray™ DM medium turn red when I inoculated it?
This is probably due to soap residue. Always clean the affected area thoroughly with 70% alcohol and air dry before obtaining the sample. The color change is usually temporary.
The InTray™ DM medium turned red after day 6, but I don’t see anything growing?
This could be due to:
- It is a yeast that is trying to grow but is being inhibited. Under microscopic examination, yeast can appear as clusters of small bubbles. Subculturing onto a Colorex™ Yeast tray will help to identify the yeast.
- A Dermatophyte and/or a saprophyte it is being inhibited. Be sure to check that you have not covered the air filter hole on the back of the tray. The organisms will take longer to grow (even go dormant) if they do not have adequate air. Do not place the inoculated tray in a 37 C incubator. Do not place the tray in direct sunlight.
There is a green fuzzy thing and a white powder and a black growth on the inoculated InTray TM – they don’t look like the pictures!
There are probably two or more organisms trying to grow. They are competing for the same nutrients and as a result colony morphology can appear different. If the growth is too heavy to examine microscopically, we recommend that you send the unopened tray to a reference lab for subculturing and identification.
What is the best way to store the InTray TM DM?
We like to say “at wine cellar temperature,” that is 15°C to 25°C (55°F to 77°F). Un-inoculated kits can remain in the box until use. Before use, please examine each tray. The media should be a clear yellow color. Any other color, cloudiness, and crystals are unacceptable. The medium should not be dry or have large bubbles. All seals should be intact.
DO NOT FREEZE OR HEAT OVER 40 C (104 F)!
The InTray TM DM can be vertically incubated.
After inoculation, the InTray TM DM can be stored in a vertical position to allow for the run-off of any condensation that may occur during colony growth. The tray lid is specifically designed to allow for the clearing of condensation for optimal viewing of the organisms. A small clear plastic storage box (no lid) or a 3”x 8” test tube drying rack are good incubators.
Do I need to do Quality Control on the InTray TM DM?
Biomed Diagnostics, Inc. routinely performs QC tests on each lot of each product throughout its shelf life. We will notify distributors and customers if we find any abnormalities and if we find additional uses for our products.
We recommend that customers perform a Quality Control test if they suspect that the InTray TM DM has been exposed to temperatures outside the guidelines.
Please notify your distributor and Biomed Diagnostics, Inc. if your InTray TM DM fails your QC testing.
What is the shelf life of the InTray TM DM kits?
InTray TM DM has an expiration date of 24 months from the date of manufacture. You should routinely receive product with greater than 6 months dating.
