Ultrasound Gel: Choosing, Using and Storing It Safely
Gel is the cheapest thing in the scan room and the easiest to overlook, yet contaminated non-sterile gel has been traced to bloodstream infection outbreaks more than once. Which gel to use for which scan, the refill and warmer rules that prevent contamination, storage, and what the probe can tolerate.
What gel does, and the types you will meet
Air between the probe and the skin reflects almost all of the sound, so the image goes dark. Gel pushes the air out and couples the probe to the patient. Medical ultrasound gel is water-based and made to be safe for probe lenses.
Standard (non-sterile) gel
Bottles, tubes and bulk containers for routine scans on intact skin. It is not sterile, even when the label says “bacteriostatic” or lists a preservative.
Sterile single-use gel
Sealed sachets or single-use tubes labelled “sterile”. One is opened for one patient and whatever is left is thrown away.
Higher and lower viscosity
Thicker gel stays where it is put on curved or upright surfaces and during long exams such as MSK and vascular work. Thinner gel spreads quickly over large areas such as the abdomen and the pregnant belly.
Gel pads (standoffs)
A solid gel block lifts the probe off very shallow structures — skin lumps, fingers, small joints — so they sit in the focal zone instead of right under the lens.
Which gel for which scan
Guidance from Public Health England (January 2021) and the Australasian Sonographers Association (December 2025) matches the gel to the infection risk of the exam, using the Spaulding classification.
| Situation | Gel | Why |
|---|---|---|
| Routine scan on intact skin — abdomen, obstetric, thyroid, MSK | Non-sterile gel from a bottle | Low risk: intact skin is a barrier |
| Any ultrasound-guided needle or line, including the first look at the site before an aseptic procedure | Sterile single-use gel, used with a sterile probe cover | Bacteria in the gel can be carried into tissue or the bloodstream |
| Broken skin, wounds and burns | Sterile single-use gel | There is no skin barrier |
| Endocavity scans (transvaginal, transrectal) with a probe cover | Single-use gel; UK guidance asks for sterile gel and the ASA prefers it | Contact with mucous membrane |
| Neonatal, intensive care and immunocompromised patients | Sterile single-use gel | The patients most vulnerable to infection |
| Patients on contact or droplet precautions | Single-use sachets, or discard the bottle after that patient | Stops the bottle carrying organisms to the next patient |
Read next Matching probe reprocessing to the same risk levels
Gel outbreaks: what went wrong
Standard gel is not made sterile, and one contaminated batch can reach many hospitals and clinics at once. Two recent examples from the United States:
- 2021: the CDC linked 119 Burkholderia stabilis infections in 10 US states, between May and September 2021, to contaminated non-sterile gel (MediChoice M500812, made by Eco-Med Pharmaceutical). Investigators found non-sterile gel was often used before or during percutaneous procedures. On 18 August 2021 the FDA told providers to stop using and discard all Eco-Med gels and lotions.
- 2025: a CDC alert on 13 May 2025 reported Paraburkholderia fungorum in two non-sterile gels, MediChoice and ClearImage, made by NEXT Medical Products — 40 isolates, mostly from blood cultures, from four US states and two other countries. Some patients had ultrasound-guided percutaneous procedures before their blood was cultured.
- Published reports describe gel-related outbreaks in hospitals in Asia, the Middle East, South America, Europe and Australia — including one traced to contaminated sterile gel used for central line insertion.
- The CDC’s advice after both US events: use only single-use gel labelled “sterile” for percutaneous procedures, train everyone who scans in correct gel use, and treat gel labelled “bacteriostatic” or “preservative” as non-sterile unless it states that it is sterile.
Bottles, refills and gel warmers
- Prefer pre-filled bottles that are thrown away when empty. Refilling from a bulk container is the practice most often linked to contamination.
- If you do refill: only refill an empty bottle, use a pump dispenser, never top up, never wash out a bottle to reuse it, label the refill date and discard the bottle after one month or when the bulk container is replaced.
- Keep the nozzle off the patient, the probe and your gloves. If the nozzle touches a patient’s skin, discard the bottle.
- Wipe the bottle, starting at the nozzle, with disinfectant before and after use, and keep it closed between patients.
- Date every bottle when it is opened and discard it after one month, or sooner if the manufacturer says so.
- Warmers: the ASA does not recommend routine warming. If you warm gel, use a dry-heat warmer rather than a water bath, keep bottles upright, do not leave them in overnight, clean and disinfect the warmer at least weekly, and never microwave gel.
Storage
- Store gel cool and dry, out of direct sunlight; the ASA suggests 15–30 °C. A store room without air-conditioning can run warmer than that in Malaysia, so keep stock in a cooled room.
- Keep bottles upright and sachets in closed boxes so the packaging stays clean and dry. Discard damaged or leaking packs.
- Rotate stock so the earliest expiry is used first, and never use gel past its expiry date.
- Record the batch or lot number when stock arrives, so you can act quickly if a recall is announced.
Probe compatibility and the patient
Use gel made for medical ultrasound
Massage oils, lotions, mineral oil and hand creams couple sound poorly, and some can damage the lens or housing. The probe care card or manual lists the gels and products the manufacturer allows.
Lens damage and probe repairWipe gel off after every scan
Remove gel from the patient and the probe straight away. Dried gel on the lens and in the seams shields organisms from the disinfectant.
Endocavity covers
Gel goes inside the cover to couple the probe, and on the outside for the patient. Oil-based products weaken latex, so use water-based ultrasound gel with latex covers.
Skin reactions
Reactions to gel are uncommon. If a patient reports one, note the brand in their record and use a different product next time.
How much to stock
- Count your scans per week by type: routine scans use bottle gel; procedures, broken skin and endocavity scans use single-use or sterile gel.
- Buy bottle sizes you will finish within a month of opening, since an opened bottle is discarded after a month.
- Keep sterile sachets where they are used — on the procedure trolley and beside the endocavity probe — not only in the store.
- Ask for gel, sachets and probe covers to be itemised as consumables in any quotation, with the lot numbers and expiry dates on delivery.
Read next Probe covers, printers and other accessoriesWhere gel and supplies go in the scan room
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Written quotes for clinics across Malaysia, handled from Batu Caves, Kota Kinabalu and Kuching.
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