Dental sterilizer monitoring · United States
What is a spore test?
A spore test, also called a biological indicator, is a preparation of bacterial spores that is put through a sterilizer cycle to check that the sterilizer works (CDC, 2008 disinfection and sterilization guideline).
Dental offices run one on every sterilizer at least weekly, incubate it with a control from the same lot, and record the result (CDC, 2003 dental infection-control guidelines).
What a spore test is
A biological indicator is an FDA-cleared commercial preparation of spores, for example Geobacillus stearothermophilus for steam, intended specifically for the type and cycle parameters of the sterilizer (CDC, 2008 disinfection and sterilization guideline).
In plain terms: bacterial spores are among the hardest things to kill. If a cycle kills the spores in the test piece, it killed the ordinary microbes on the instruments. The test checks the outcome of the cycle itself.
Why offices test at least weekly
Correct functioning of sterilization cycles should be verified for each sterilizer by the periodic use, at least weekly, of biological indicators (CDC, 2003 dental infection-control guidelines).
CDC's short summary for dental settings says the same thing in one line: a spore test should be used at least weekly to monitor sterilizers (CDC, 2016 summary of infection prevention practices).
The sources quoted on this page say "at least weekly" and nothing about how to space the tests, and they set no separate schedule for a sterilizer that is used only part of the time. Schedules that go beyond this baseline are covered by the guides listed under Read next.
The control from the same lot
A spore test is run with a matching control: a biological indicator and a control from the same lot number (CDC, 2003 dental infection-control guidelines).
The control is not processed through the sterilizer. It is incubated together with the test indicator (CDC, 2003 dental infection-control guidelines).
In plain terms, the control answers one question: can the spores from this lot still grow? Without it, "no growth" could mean a good cycle or a test that was already dead. With it, the office knows the test was alive going in.
In the office or by mail
In-office biological monitoring is available, and mail-in sterilization monitoring services, for example from private companies or dental schools, can also be used to test both the BI and the control (CDC, 2003 dental infection-control guidelines).
Both routes test the same pair, the test indicator and its control (CDC, 2003 dental infection-control guidelines). What changes is where the spores grow and how the result travels back.
| What changes | In the office | By mail |
|---|---|---|
| Where the spores are incubated | In your office, by your own staff. | At the monitoring service, for example a private company or a dental school. |
| How the result reaches you | Your staff reads the indicator after incubation. | The service sends back a report. |
| What a good log keeps | The incubation start time and the time the result was read. | The service name, the date sent, the report ID and the date received. |
What to record
The result of every spore test is written down, and sterilization monitoring records, mechanical, chemical and biological, are kept long enough to comply with state and local regulations (CDC, 2003 dental infection-control guidelines).
A good spore test record holds the sterilizer and the cycle type; the load the test rode in; the indicator's product, lot number and expiration date; a note that the control came from the same lot and what it showed; how the test was run, in-office or by mail, with the dates; the result, negative, positive or invalid, and the date it was read; and who entered it.
How long to keep it? The sources quoted on this page give no number of years. They leave the length to state and local regulations (CDC, 2003 dental infection-control guidelines).
The exact wording behind this page
Each rule on this page rewrites one of the seven passages below and keeps its limits. The ID points to the row in our source pack; the page number is where the passage sits in the source document.
| ID | Source and quote |
|---|---|
| D08-1 | "Use biologic indicators to monitor the effectiveness of sterilizers at least weekly with an FDA-cleared commercial preparation of spores (e.g., Geobacillus stearothermophilus for steam) intended specifically for the type and cycle parameters of the sterilizer."CDC/HICPAC, Guideline for Disinfection and Sterilization in Healthcare Facilities, 2008 — recommendation 16.d |
| C03-1 | "Monitor sterilizers at least weekly by using a biological indicator with a matching control (i.e., biological indicator and control from same lot number)"CDC, Guidelines for Infection Control in Dental Health-Care Settings — 2003, rec. VI.F.6, p. 43 |
| C03-2 | "Correct functioning of sterilization cycles should be verified for each sterilizer by the periodic use (at least weekly) of BIs"CDC, Guidelines for Infection Control in Dental Health-Care Settings — 2003, p. 24 |
| C03-5 | "A control BI, from the same lot as the test indicator and not processed through the sterilizer, should be incubated with the test BI"CDC, Guidelines for Infection Control in Dental Health-Care Settings — 2003, p. 24 |
| C03-6 | "In-office biological monitoring is available; mail-in sterilization monitoring services (e.g., from private companies or dental schools) can also be used to test both the BI and the control."CDC, Guidelines for Infection Control in Dental Health-Care Settings — 2003, p. 24 |
| C03-21 | "Results of biological monitoring should be recorded and sterilization monitoring records (i.e., mechanical, chemical, and biological) retained long enough to comply with state and local regulations."CDC, Guidelines for Infection Control in Dental Health-Care Settings — 2003, p. 25 |
| SUM-1 | "A spore test should be used at least weekly to monitor sterilizers."CDC, Summary of Infection Prevention Practices in Dental Settings, PDF p. 15 |
Read next
- How often must a dental office spore test its sterilizer? — what sits on top of the weekly baseline, and how states differ.
- In-office or mail-in spore testing: how each works and what to record — the two routes in practice.
- What to do when a dental sterilizer fails a spore test — the steps after a positive result, with their sources.
- Free dental sterilizer spore test (BI) log — a printable weekly log with a column for the control.
This page is not legal advice; check your state board's current rules.
Keep these results in one place
Dental Logbook is being built to keep spore test results, controls and loads in one record for US dental offices. Pilot offices shape what it records.
Dental Logbook is in development: join the free pilot