Delhi · Gurugram · Bangalore · Baddi · Bahadurgarh

Medical Device Sterility Testing — ISO 11737-2

Every terminally sterilised medical device reaching the market must demonstrate sterility through a validated process — and the test of sterility per ISO 11737-2 is the microbiological evidence that supports it. Auriga Research provides NABL-accredited medical device sterility testing by membrane filtration and direct inoculation for implants, catheters, wound dressings, sutures, IV / transfusion sets, and single-use disposables, supporting sterilisation validation dossiers accepted by CDSCO, FDA, and CE Notified Bodies.

This service is scoped specifically to ISO 11737-2 (test of sterility of medical devices) — distinct from pharmaceutical sterility per USP <71>. Our scope covers bacteriostasis / fungistasis (B/F) method-suitability validation, the test of sterility itself in FTM and SCDM media, positive and negative controls, sample-item portion (SIP) rationale for large devices, and sterility-failure investigation. Test-of-sterility data feeds directly into ISO 11135 (EO) and ISO 11137 (radiation) sterilisation validation alongside the supporting bioburden (ISO 11737-1) data.

Backed by the Arbro Group's analytical heritage — Arbro Lab since 1990, Auriga Research since 2007 — with NABL ISO/IEC 17025 accreditation, our reports are accepted by CDSCO licensing authorities, FDA 510(k) reviewers, EU CE Notified Bodies, and contract sterilisers. Need pharmaceutical or parenteral sterility per USP <71> instead? See our pharmaceutical microbiological & sterility testing service.

Test of sterility: 14-day incubation (fixed by ISO 11737-2) | B/F validation in parallel

Get a Quote Call +91-7428116100

Sterility Testing Scope

Each capability is mapped to its ISO 11737-2 method or workflow step so sterility-assurance and QA teams can match scope to the validation dossier at a glance.

ISO 11737-2

Test of Sterility

Test of sterility of medical devices per ISO 11737-2 — used in the definition, validation, and maintenance of a sterilisation process.

Membrane Filtration

Membrane Filtration Method

Preferred method for devices that can be flushed or eluted — the rinse is filtered and the membrane incubated in growth media.

Direct Inoculation

Direct Inoculation / Immersion

Whole device or representative portion immersed directly in media for devices that cannot be filtered.

B/F

Bacteriostasis & Fungistasis

Method suitability (B/F validation) to prove the device or its residues do not inhibit microbial recovery — required before any test of sterility.

FTM

Anaerobic / Aerobic Culture

Fluid thioglycollate medium (FTM) incubated at 30–35 °C for aerobic and anaerobic organisms.

SCDM / TSB

Fungal / Aerobic Culture

Soyabean casein digest medium (SCDM / TSB) incubated at 20–25 °C for fungi and aerobic organisms.

Controls

Method Controls

Positive (growth promotion) and negative (sterility) controls run with every batch to validate the test system.

SAL 10⁻⁶

Sterility Assurance Level

Test of sterility supporting demonstration of the SAL 10⁻⁶ target required for terminally sterilised devices.

ISO 11135 / 11137

Sterilisation Validation Link

Test of sterility feeding EO (ISO 11135) and radiation (ISO 11137) sterilisation validation and routine release.

Investigation

Failure Investigation

Sterility test failure investigation and retest per ISO 11737-2 / ISO 11737-3 guidance.

How It Works

Get a Quote

Share your device type, sterilisation method (EO / radiation / steam), and regulatory target (CDSCO / FDA / CE). Your dedicated SPOC confirms the testing scope, the ISO 11737-2 method (membrane filtration vs direct inoculation), the bacteriostasis / fungistasis validation needed, and the sample-item portion (SIP) for your specific device before you dispatch anything.

Send Your Sample

Dispatch sterile-handled device samples with a completed Test Request Form to the nearest Auriga lab. Each sample is individually bar coded and registered in YLIMS, Auriga's in-house Laboratory Information Management System, upon receipt. Testing begins within 24 hours of sample registration.

Testing and QA Review

Your sample is tested per the validated ISO 11737-2 method by Auriga's microbiology team in our clean-room facility — B/F method suitability first, then the test of sterility in FTM and SCDM media with positive and negative controls, observed across the 14-day incubation period. Every result passes through a formal internal QA review and sign-off before the report is generated.

Receive Your NABL Report

Your NABL-accredited sterility test report is delivered digitally after the mandatory incubation completes. Reports carry Auriga's NABL accreditation under ISO/IEC 17025:2017, are accepted by CDSCO, FDA 510(k), CE Notified Bodies, and contract sterilisers for ISO 11137 / 11135 dose audits, and reconcile with the supporting bioburden data. You can track sample status in real time through YLIMS.

Turnaround Time

Service	Standard TAT	Express
Bacteriostasis / fungistasis (B/F) validation	14–18 business days	On request
Test of sterility (membrane filtration / direct inoculation)	14-day incubation + reporting	— fixed by ISO 11737-2
Routine batch-release test of sterility	14-day incubation + 2–3 days	— fixed by ISO 11737-2
Sample-item portion (SIP) rationale	5–7 business days	On request
Sterility failure investigation & retest	Per ISO 11737-2 / -3	On request
Combined bioburden + test of sterility programme	20–25 business days	On request

The 14-day incubation period is mandated by ISO 11737-2 and cannot be shortened — "express" applies to scheduling, B/F validation, and reporting around the fixed incubation, not the incubation itself.

Who Needs Medical Device Sterility Testing

Manufacturers of terminally sterilised devices establishing sterilisation validation for CDSCO / FDA / CE under ISO 11135 (EO) or ISO 11137 (radiation).
Class C / Class D implant manufacturers (orthopaedic, cardiovascular, ophthalmic) requiring test of sterility for high-risk device dossiers.
Single-use disposable manufacturers (syringes, catheters, IV / transfusion sets, surgical kits) running batch-release sterility.
Wound dressing, suture, and surgical-mesh manufacturers verifying sterility of finished sterile product.
Contract sterilisers needing test-of-sterility data for ISO 11137 dose audits and EO cycle re-qualification.
Quality teams running routine batch-release and periodic sterility surveillance.
Reprocessing and refurbishing facilities verifying sterility of reusable devices after re-sterilisation.
Regulatory consultants assembling CDSCO Form MD-9 / MD-15, FDA 510(k), and EU MDR sterilisation validation packages.
Post-market complaint investigation teams responding to a suspected sterility failure in distributed product.
R&D teams qualifying a new device design or a new sterile barrier system that changes the sterility-test approach.

Why Auriga for Medical Device Sterility Testing

NABL scope explicitly covering ISO 11737-2

Device sterility testing is explicitly listed on our NABL scope certificate under ISO 11737-2 — not borrowed from a pharmaceutical USP <71> scope. CDSCO, FDA, and CE Notified Bodies accept the report without follow-up scope verification.

Device-scoped, not pharma-scoped

Reports are framed for the device sterilisation-validation pathway (ISO 11737-1 / -2, ISO 11135, ISO 11137) — the correct audience and standard for a device manufacturer, not a re-labelled pharmaceutical sterility report.

Clean-room microbiology facilities

Dedicated clean-room sterility suites with environmental monitoring under ISO 14644 control — eliminates false-positive growth from lab air, the most common audit finding on sterility reports from non-specialist labs.

Bioburden + sterility under one roof

Test of sterility and bioburden (ISO 11737-1) run in the same lab so the two data sets reconcile within one sterilisation validation dossier — no cross-lab handover or data mismatch.

CDSCO / FDA / CE acceptance trail

Reports routinely accepted in CDSCO Form MD-9 / MD-15 submissions, FDA 510(k) sterility sections, and CE technical files reviewed by major Notified Bodies (BSI, TÜV SÜD, DEKRA, DNV).

Arbro Group analytical heritage

Established analytical heritage through the Arbro Group (Arbro Lab since 1990, Auriga Research since 2007), with NABL ISO/IEC 17025 accreditation — the audit trail device manufacturers, contract sterilisers, and regulatory consultants look for in a sterility partner.

Related Services

Frequently Asked Questions

How is medical device sterility testing different from pharmaceutical sterility testing (USP <71>)?

They share the same microbiological principle — incubation in fluid thioglycollate (FTM) and soyabean casein digest (SCDM) media with growth observation — but they are scoped to different products and standards. Medical device sterility testing follows ISO 11737-2, which is written specifically for the test of sterility performed in the definition, validation, and maintenance of a device sterilisation process. Pharmaceutical sterility testing follows USP <71> / IP / BP / EP and is scoped to drug products, parenterals, and APIs. The device standard handles device-specific challenges — large or irregular geometries, sample-item portions, eluate testing, and the link to ISO 11135 / 11137 sterilisation validation. If you need pharmaceutical or parenteral sterility per USP <71>, use our pharmaceutical microbiological testing service; if you need device sterility per ISO 11737-2, this is the correct service.

What is the difference between membrane filtration and direct inoculation?

Membrane filtration is the preferred ISO 11737-2 method where the device can be flushed or eluted: the rinse / eluate is passed through a 0.45 µm membrane that retains any microorganisms, the membrane is rinsed to remove inhibitory residues, then incubated in growth media. It is preferred because it physically separates organisms from any antimicrobial residue on the device. Direct inoculation (immersion) is used when a device cannot be filtered — the whole device or a representative sample-item portion is immersed directly in the media. Direct inoculation requires careful bacteriostasis / fungistasis validation because device residues stay in contact with the media throughout incubation.

What is bacteriostasis and fungistasis (B/F) validation, and why is it mandatory?

Bacteriostasis / fungistasis (B/F) validation — also called the method suitability or validation test — demonstrates that the device, its materials, or its sterilisation residues do not inhibit the growth of microorganisms in the sterility test. Low numbers of challenge organisms (≤ 100 CFU of specified strains) are introduced into the test system with the device present; if they grow as expected, the method is validated for that device. B/F validation is mandatory before any test of sterility result can be considered valid — a sterility "pass" from a method that actually suppresses growth would be a false negative. Auriga performs B/F validation as the first step of every new device sterility programme.

How does sterility testing fit into ISO 11135 (EO) and ISO 11137 (radiation) sterilisation validation?

Test of sterility per ISO 11737-2 is one element of the overall sterilisation validation, alongside bioburden (ISO 11737-1) and the sterilisation-method standard (ISO 11135 for EO, ISO 11137 for radiation). In radiation sterilisation, the test of sterility is used in dose-setting verification and the periodic dose audit; in EO sterilisation it supports the microbiological performance qualification. The device standards are explicit that a test of sterility alone does not "prove" sterility of a batch — sterility is assured by the validated process delivering the SAL 10⁻⁶, with bioburden and test-of-sterility data supporting it. Auriga runs bioburden and test of sterility together so the data sets reconcile within one validation dossier.

What sample quantity is required for a medical device sterility programme?

Sample quantity depends on the device size, the method, and the test stage. B/F validation typically requires 6–12 devices or device portions across the challenge-organism arms. The routine test of sterility requires a number of units based on batch size and the ISO 11737-2 sampling rationale — commonly 10–20 units per batch for membrane filtration or direct inoculation. Large or complex devices use a representative sample-item portion (SIP) determined first, which itself needs additional units. Confirm the exact quantity with your SPOC at the quote stage, particularly for high-value implantable devices where sample destruction has a material cost.

What is the regulatory consequence of inadequate sterility data on a device submission?

Sterility evidence is a core element of every sterile-device file. (1) CDSCO MD-9 / MD-15 applications without ISO 11737-2 test-of-sterility and the supporting bioburden / sterilisation validation are returned with a sterility-assurance deficiency — typically blocking the registration by 3–6 months. (2) FDA 510(k) submissions with thin sterility / sterilisation sections trigger an Additional Information (AI) request. (3) EU MDR technical files lacking ISO 11737-2 conformity are a Notified Body non-conformance. (4) Post-market: a sterility failure in distributed product triggers CDSCO Materiovigilance / FDA MAUDE reporting and a full recall, and the root-cause investigation requires historical bioburden and test-of-sterility data. A robust sterility programme is materially cheaper than reacting to a field sterility incident.

Can Auriga support contesting a CDSCO or Notified Body finding on sterility with additional data?

Yes. Gap-fill sterility testing in response to a CDSCO deficiency, FDA AI request, or Notified Body non-conformance is a routine workflow. The path is: (1) review the regulator's specific finding with your SPOC; (2) identify whether the gap requires additional test-of-sterility batches, fresh B/F validation, a SIP rationale, or reconciliation with the bioburden / dose-audit data; (3) run the targeted top-up programme — not a full re-validation; (4) issue an NABL-accredited supplementary sterility report formatted as an addendum to the original sterilisation validation. Express turnaround is available within the limits of the mandatory 14-day incubation period for time-critical regulatory windows.

Get a Tailored Recommendation

Talk to a Testing Expert