We wanted to see how our Standard and Premium 3 mL cartridges performed under independent microbial testing, alongside a cartridge bought from HDRSMTMED on AliExpress. We sent the samples to Verifi Labs and paid for the testing. Both Grey Depot samples passed with no growth detected. The HDRSMTMED sample failed the aerobic microbial count test, with 6 CFU per cartridge reported.
The results, side by side
All three reports list the same method, TAMC / TYMC Microbial Detection, using PetriFilm Plates. The laboratory received the samples on 15 September, recorded the analysis date as 22 September and issued the reports on 23 September 2026.
| Submitted sample | Aerobic microbial count (TAMC) | Yeast and mould count (TYMC) | Report outcome |
|---|---|---|---|
| Grey Depot Standard | No growth detected: Pass | No growth detected: Pass | PASS |
| Grey Depot Premium | No growth detected: Pass | No growth detected: Pass | PASS |
| AliExpress / HDRSMTMED | 6 CFU / Cartridge: Fail | No growth detected: Pass | FAIL |
Why we included an AliExpress cartridge
If you're comparing empty 3 mL glass cartridges online, product photos only tell you so much. They show the cartridge, its closures and its packaging. They don't tell you what a microbial test will find.
We bought the HDRSMTMED cartridge for comparison. We don't sell that seller's cartridges. We do sell the Standard and Premium cartridges in this test, and we commissioned all three reports. You can inspect the findings below rather than taking our summary on trust.
What failed on the HDRSMTMED sample?
The aerobic microbial count test, abbreviated to TAMC, checks for microorganisms that grow under the test's aerobic conditions. Verifi recorded 6 colony-forming units per cartridge and marked that result Fail. A colony-forming unit, or CFU, is a measure of microbial growth; it isn't the name of an organism.
The separate yeast and mould test, TYMC, showed no growth and passed. That distinction matters: this was a failed aerobic count result, not a failed yeast and mould result.
The report names the vendor as Ali Express / HDRSMTMED, the sample as 6EPJ and the report as KAPYS3LQ. It doesn't identify the organisms or establish where the growth originated. The finding is clear enough without guessing: microbial growth was detected in this sample, and the laboratory marked the report FAIL.
Read the complete HDRSMTMED report, KAPYS3LQHDRSMTMED sample — report KAPYS3LQ
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Standard and Premium both passed
Our Standard sample, 7MSB, showed no growth in either test. Verifi marked both results Pass and issued report 4ARZ2XJQ with an overall PASS.
Our Premium sample, 6HBG, returned the same result: no growth in either test, both marked Pass. Its report is F9G6YQ2H.
We were pleased to see both results. Customers can now open each report directly from the relevant listing, and the complete reports are also linked here.
Read the complete Standard report, 4ARZ2XJQ Read the complete Premium report, F9G6YQ2HGrey Depot Standard sample — report 4ARZ2XJQ
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Grey Depot Premium sample — report F9G6YQ2H
View supporting photo page
Our cartridges are sterilised differently
Standard cartridges have the stopper, also called the plunger, installed before steam sterilisation in an autoclave. Premium cartridges are packaged with the washed stopper separate inside the same sealed pouch, then terminally sterilised using ethylene oxide, or EO, and aerated. Keeping the stopper separate exposes its surfaces during that sterilisation cycle.
Both ranges are supplied sterilised. The independent reports add a check on microbial growth in the samples we sent; they don't replace the manufacturing process.
The lab calls these tests microbial enumeration, not a full sterility test. No growth detected is the result for our samples. Detectable microbial growth and a failed aerobic count is the result for the HDRSMTMED sample. Those are the findings we can show you.
Compare Standard, Premium and Gold cartridge specificationsWhat to look for when reading a cartridge CoA
Start with the sample name and the report number. Then read each test row, not just the large PASS or FAIL at the top. In this comparison, the HDRSMTMED report contains a passing yeast and mould result as well as the failed aerobic count.
Check the dates and the batch field too. All three reports say Batch / Lot: Not set. These are results for the identified samples, not certificates covering every cartridge from either seller or future deliveries.
The screenshots reproduce the full report pages without cropping or annotations. Each PDF also includes the laboratory's supporting photos. Open the images at full size or download the complete PDF if you want to inspect the details.
Where to find our cartridge reports
The Standard and Premium listings now each have their own Verifi Labs CoA link under Learn more. That keeps the evidence beside the product it belongs to. Gold was not part of this comparison; its existing manufacturer report is a separate document.
View Standard 3 mL cartridges and the CoA View Premium 3 mL cartridges and the CoA