Sterilamp II, MagnaAmp and Spordex: Spore Strip and Ampoule BIs Compared
Three product names, two manufacturers, and one decision that a sterile processing department or clinic has to make before ordering: which biological indicator format fits the workflow that will actually run it. Format, not brand, is what determines whether the result arrives the next morning or after a laboratory step nobody has been assigned to perform.
Mesa Labs publishes SterilAmp II along with the 5230 as liquid self-contained biological indicators, and publishes MagnaAmp as a biological indicator in the same life-science sterilization control range. STERIS publishes Spordex as biological indicator strips and discs. The names look interchangeable in a catalogue row; the handling does not.
How do the formats differ in day-to-day use?
| Format | Published example | Incubation | Readout | Typical setting |
|---|---|---|---|---|
| Liquid self-contained indicator | SterilAmp II and 5230 | Dry-block or water-bath incubator, as supplied | Visual change after incubation | Clinical and laboratory benches |
| Ampoule indicator | MagnaAmp | Incubator at the indicator's stated temperature | Visual change in the sealed unit | Contract sterilization, manufacturing |
| Spore strip | Spordex strips | Transferred to culture medium, then incubated | Grows or does not grow, against a control | Validation and laboratory work |
| Spore disc | Spordex discs | Transferred to culture medium, then incubated | Grows or does not grow, against a control | Confined spaces, validation and laboratory work |
The self-contained column is the one a clinic recognises: unit in, incubate, read. The strip and disc column adds a transfer step, which means medium, technique and a control, and a handling error at that step looks exactly like a sterilization failure.
What does the spore organism tell you?
The organism is selected for the cycle being monitored. Steam monitoring uses a thermophilic spore former with an incubation temperature in the range of roughly 55 to 60 degrees Celsius, which is why a dry-block incubator sits at that temperature. Ethylene oxide and dry heat monitoring use a different organism, incubated in a lower range, as set out in the ISO 11138 series. Two platforms in one department therefore means two incubation regimes, kept physically separate.
That separation has a documentation consequence. An indicator read at the wrong incubation temperature produces a result nobody can defend, and the error is invisible on a log sheet unless the sheet names the incubation regime. Departments running both steam and low-temperature cycles should print the incubation temperature on the log itself, not in a procedure document filed elsewhere.
Which format fits which operation?
A dental, veterinary or family-practice clinic processing loads every working day is served by a self-contained format and a dry-block incubator: 24 hours to a result, no media, no transfer, no positive control to hold. Where a faster answer changes a clinical schedule, fluorescence formats read in a compatible reader compress that to minutes. A hospital CSSD or contract sterilizer, by contrast, may hold strip and disc programmes precisely because the media and the controls are already part of the department's laboratory capability.
For clinics, the clinic-side equivalents are priced openly rather than quoted: a 24-hour self-contained indicator at $2.40 per test, a 24-well dry-block incubator at CA $279 for in-house incubation, and the Rapid Reader seed trial for departments evaluating fluorescence readout speed before committing to a reader.
What should be verified before ordering any of the three?
Four items, in this order: the format and whether the transfer step is something you are staffed to perform; the incubation temperature the supplier states; the printed lot number and expiry on each unit, since that is what the audit file depends on; and the cycle the indicator is intended for, because a steam indicator in an ethylene oxide load is not a monitoring result at all. Buyers comparing across catalogues can use the same four fields, which is also how sterilization monitoring items should be listed internally so that the specification survives the next reorder.
References
- Mesa Labs - MagnaAmp biological indicator (checked 16 September 2026)
- Mesa Labs - SterilAmp II and 5230 liquid self-contained biological indicators (checked 16 September 2026)
- STERIS Life Sciences - Spordex biological indicator strips and discs (checked 16 September 2026)
Related Reading
- Sterilization compliance hub: monitoring, logs and provincial rules
- Biological indicator kill time explained: what the incubation window means
- Microbiological monitoring for labs and food manufacturing
- Biological Indicator Formats Compared: Self-Contained vs Strip vs Ampoule Across 6 Suppliers
- free Ontario sterilization compliance log
- printable autoclave sterilization log sheet (free)
Frequently Asked Questions
Is SterilAmp II the same thing as a spore strip?
No, and the difference decides where the product can be used. SterilAmp II is published by Mesa Labs as a liquid self-contained biological indicator, meaning the spores and the culture medium are in one unit that is incubated and read as supplied. A spore strip is filter paper carrying the spores, which has to be transferred to culture medium and incubated, and then read against a control. One is a bench process; the other is a laboratory process.
What is MagnaAmp used for?
Mesa Labs publishes MagnaAmp as a biological indicator within its life-science sterilization control range, alongside the SterilAmp II and 5230 liquid self-contained formats. Ampoule formats are used where a sealed, self-contained unit suits the process being monitored, including contract sterilization and manufacturing settings where indicators are handled in volume rather than one at a time.
Why would a clinic use a strip or disc indicator at all?
Usually it does not. Strips and discs suit validation work, contract sterilization and laboratory settings, where the incubation and the positive control are handled by trained staff with the media on hand. In a dental clinic, the transfer-to-media step introduces a handling variable that self-contained indicators are designed to remove.
Does a spore strip come with documentation for an audit?
STERIS states that each disc package and strip glassine envelope carries a printed lot number and expiration date for traceability, and that the strips and discs meet the performance parameters set by USP, ANSI, AAMI and ISO 11138. That is the documentation an audit file needs, and it is also the reason a strip programme has to be managed as a laboratory activity rather than as a shelf item.
Last updated: September 2026. CliniEco Medical holds MDEL #35334 issued by Health Canada, and supplies clinics, long-term care homes and home-care programs across Canada.
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