Why This Station Is Tested
Surgical scrub technique and maintaining a sterile field are fundamental patient safety competencies. The OSCE tests whether you can perform the WHO-recommended surgical hand preparation technique, correctly gown and glove without contaminating the sterile field, and demonstrate theatre etiquette. This station is frequently included in surgical OSCE circuits and is a common DOPS (Directly Observed Procedural Skills) assessment.
Before You Begin
Ensure your preparation before entering the scrub area:
- Remove watches, jewellery (rings, bracelets), and nail varnish — these harbour microorganisms and prevent effective scrubbing
- Ensure nails are short and clean
- Surgical scrub suit, hat (covering all hair), and mask worn and fitted correctly before scrubbing
- Mask must cover nose and mouth — check fit; beards require specialist hoods
- Eye protection worn if splash risk
WHO Surgical Hand Preparation — Scrub Technique
The WHO recommends two acceptable methods: surgical hand rub (alcohol-based, preferred) and surgical hand scrub (antiseptic soap with a brush). For most OSCEs, the traditional surgical scrub is tested.
Step-by-Step Surgical Hand Scrub
Duration: 3–5 minutes total (some institutions specify different times — follow local protocol)
Antiseptic agents used: Chlorhexidine gluconate 4% (Hibiscrub) or Povidone-iodine 7.5% (Betadine).
| Step | Action |
|---|---|
| 1 | Open scrub brush, nail pick, and antiseptic dispensed before touching the tap (use elbow/knee/sensor tap) |
| 2 | Wet hands up to 2 inches above the elbows, keeping hands higher than elbows throughout |
| 3 | Apply antiseptic to hands and lather |
| 4 | Clean under each fingernail with nail pick — remove nail pick, discard |
| 5 | Scrub each surface of each finger (4 sides), web spaces, palms, dorsum of hands — count-based or time-based depending on local protocol |
| 6 | Proceed to scrub wrists then forearms with circular movements |
| 7 | Rinse from fingertips to elbows — keeping hands higher than elbows at all times (water flows away from clean hands) |
| 8 | Repeat steps 5–7 for the second scrub (some protocols use 3 passes) |
| 9 | Final rinse from fingertips to elbows |
| 10 | Hold hands up in front of you, move to theatre without touching anything |
⚠️ Red Flag
Never lower your hands below your elbows after scrubbing — if you touch anything non-sterile, you must re-scrub.
Drying and Gowning
- 1Enter the theatre and take a sterile towel from the scrub nurse (pick up from the top — avoid contaminating the rest of the pack)
- 2Dry each hand and arm separately with each end of the towel — use a patting motion, work from fingertips towards elbow (never back towards hands)
- 3Discard towel
- 4Pick up the gown from the scrub nurse, holding it at the inside neckline
- 5Unfold away from you — ensure it does not touch anything non-sterile
- 6Insert arms simultaneously — advance until hands are just inside the cuffs (closed gloving) or until hands emerge (open gloving)
- 7Scrub nurse or assistant ties the back ties (you cannot touch your own back — it is non-sterile)
- 8Take the card waist tie from the scrub nurse, hand the other end to someone non-scrubbed, turn 360°, take back the tie and tie at your front — this maintains back sterility
Gloving — Closed vs Open Technique
Closed gloving (preferred for scrub team): hands remain inside the gown cuffs. Use the sleeve to pick up the glove, place on the opposite sleeve cuff, and pull over the closed hand. Safer — reduces risk of skin contact with glove exterior.
Open gloving (for bedside procedures): hands emerge from cuffs. Pick up first glove by the inner folded cuff (non-sterile), place on hand. Pick up second glove by the sterile outer surface (using already-gloved hand), and place on second hand. Unfold cuffs.
Maintaining the Sterile Field
💡 Tip
The sterile field is above waist level and in front of you. Never turn your back to the sterile field, and never reach across another scrubbed person's sterile field.
| Sterile | Non-sterile |
|---|---|
| Gloved hands above waist | Anything below waist |
| Front of gown (chest to waist) | Back of gown |
| Sterile drapes above table level | Anything touching unsterile surfaces |
| Instrument trolley surface | Trolley legs and wheels |
Rules to follow:
- Do not leave the sterile field unattended
- If you suspect contamination (glove puncture, gown soaked through), stop and change
- If in doubt, change — "if in doubt, throw it out"
- Face other scrubbed personnel when passing (face to face or back to back — never scrubbed to non-scrubbed)
- Drapes must remain above the table level at all times
Theatre Etiquette
- Enter theatre by pushing the door with your back or hip (hands not contaminated)
- Minimise talking in theatre (airborne contamination risk)
- Do not cross the sterile field
- Scrub personnel move back-to-back or face-to-face
- If unsure of your sterility — ask and change
Frequently Asked Questions
"What is the difference between surgical scrub with a brush and alcohol-based surgical hand rub, and when is each used?"
Surgical hand scrub uses an antiseptic detergent (typically chlorhexidine 4% or povidone-iodine 7.5%) with a sterile brush to mechanically remove skin flora and transient microorganisms from the hands, wrists, and forearms over 3–5 minutes. Alcohol-based surgical hand rub (ABHR) — such as Sterillium or WHO-formulation rub — is applied to clean, dry hands and rubbed in for the manufacturer-recommended time (typically 90 seconds to 3 minutes) covering all surfaces up to the elbow in a specific sequence. ABHR is WHO-preferred because it is faster, causes less skin damage (alcohol combined with emollients is gentler than repeated scrubbing), and has superior antimicrobial efficacy against most organisms including bacteria and some viruses. However, ABHR is not effective against visibly soiled hands or Clostridium difficile spores — in these cases, hand washing with soap and water (or antiseptic soap) is required first. In clinical practice in UK theatres, the choice depends on local protocol and surgeon preference, but ABHR is increasingly standard.
"What should you do if you suspect your sterile glove has been punctured during an operation?"
If you suspect glove puncture — from a needle-stick, instrument injury, or visible defect — you must change the glove immediately, as this constitutes a break in the sterile field. Alert the scrub nurse and circulating nurse: step back from the sterile field, allow the circulating nurse to remove the outer glove (using aseptic technique), and the scrub nurse replaces it with a new sterile glove. If a hollow-bore needle was involved, this is also a sharps injury and must be managed according to local occupational health protocol: the wound is encouraged to bleed (do NOT suck), washed with soap and water, and an incident form completed urgently so that blood-borne virus exposure can be assessed. In theatre, double gloving — wearing two pairs of gloves — is recommended for procedures with high perforation risk (orthopaedic bone work, prolonged procedures) as it significantly reduces the rate of inner glove perforation. Mentioning double gloving as a preventive measure in the OSCE demonstrates awareness of surgical safety.
"Why must hands be kept higher than elbows throughout the surgical scrub and after?"
The principle is to allow water and soap (or rinse water) to flow from the cleanest area (the fingertips, which have been scrubbed most thoroughly) towards the dirtier area (the forearm), and ultimately off the elbow, rather than back towards the hands. If hands drop below elbows, contaminated water from the forearms drains back over the already-clean hands, recontaminating them. This is the same principle as in medical hand hygiene — always work from clean to dirty. After scrubbing, holding the hands up also keeps them away from non-sterile surfaces (trolleys, gown ties, clothing) and is a visible signal to others that you are scrubbed and must not be touched. In the OSCE, narrate this principle when asked: "I keep my hands elevated to ensure that water flows away from the clean fingertips towards the elbows, preventing contamination of the scrubbed surfaces."
"What are the zones of sterility on a surgical gown and how do you maintain them?"
The sterile zone of a surgical gown is the anterior surface from chest level to waist level, and the sleeves from just above the elbow to (but not including) the glove cuffs. The back of the gown is always considered non-sterile, as it cannot be directly visualised or maintained by the scrubbed practitioner. Below the waist level is non-sterile, as are the neckline and axillary areas. The cuffs of the gown under the gloves are a zone of uncertainty — with closed gloving, the cuff remains covered and sterile; if the glove rolls back and exposes the gown cuff, it is contaminated. Practical implications: always keep your hands in front of you at chest to waist level; never fold your arms (hands would go to non-sterile sides or axillae); when turning, cross your arms across your chest and turn; sit with hands on your lap above waist level. If you must reach across the table, lean forward from the waist — do not drop your hands.
"How do you assist a non-scrubbed person to tie your surgical gown without breaking sterility?"
The front of the gown has a waist tie with a card attached. After gowning, the scrub nurse or another scrubbed member hands you the card (the string is attached). You hold the card out to a non-scrubbed member of the team (the circulating nurse or anaesthetist) who takes only the card — they must NOT touch the string. You then turn 360° in place (keeping the string taut), which wraps the string around your back and brings it back around to your front. You then retrieve the string from the card (which the non-scrubbed person is still holding) by pulling the string — it pulls free from the card. Tie the string at your front. This manoeuvre ensures the back tie goes around your back and ties at the front while the circulating nurse holds only the non-sterile card, which is then discarded. If done correctly, the back of the gown is covered by the front panel and your back sterility is maintained. Narrating this step clearly in the OSCE demonstrates procedural knowledge.
"What organisms are surgical antiseptic scrub agents most effective against and why does this matter?"
Chlorhexidine gluconate (CHG) 4% is effective against Gram-positive bacteria (including MRSA and Staphylococcus epidermidis), Gram-negative bacteria, fungi, and has limited virucidal activity. Critically, chlorhexidine has a residual (persistent) effect — it binds to the skin and continues to reduce bacterial counts for several hours after application, making it ideal for surgical scrubbing where re-contamination must be minimised throughout a long procedure. However, it is NOT effective against C. difficile spores or TB. Povidone-iodine 7.5% has broader antimicrobial activity including mycobacteria and some viruses, but has no residual effect — bacterial counts recover faster after iodine than after chlorhexidine. For this reason, chlorhexidine is preferred for prolonged procedures. Alcohol-based handrubs are rapidly bactericidal, fungicidal, and virucidal (enveloped viruses), with no residual effect on their own but often combined with chlorhexidine for lasting activity. Knowing these distinctions is clinically relevant for choosing antiseptic agents in different surgical contexts.
Related guides: Wound Care and Suturing OSCE · Perioperative Care OSCE · Urinary Catheterisation OSCE · Venepuncture and Cannulation OSCE · IM and Subcutaneous Injection OSCE