Common Mistakes When Administering Injections and How to Avoid Them
, by Andrew Odgers, 14 min reading time
Injection Technique
Common Mistakes When Administering Injections and How to Avoid Them
Injection errors cause patient harm ranging from minor discomfort to serious medication incidents. Many of the most common mistakes are entirely preventable with correct preparation, technique, and post-injection practice. This guide identifies the errors that occur most frequently across subcutaneous, intramuscular, and intravenous injections and gives the practical correction for each.
Before you inject
Preparation and setup mistakes
Wrong needle gauge or length for the route and patient
Using a needle that is too fine for the medication viscosity, too short for the intended tissue depth, or too wide for the patient's anatomy is one of the most common and consequential preparation errors. A 25 gauge needle selected for a viscous intramuscular preparation will require excessive plunger force, produce incomplete delivery, and create patient discomfort without delivering the dose to the correct tissue layer. A 25 mm needle used for deltoid IM injection in a patient with substantial overlying subcutaneous tissue deposits the medication subcutaneously rather than intramuscularly, compromising absorption.
The correction is to select gauge and length based on the injection route, the medication's viscosity, and the individual patient's anatomy. Refer to the licensed product directions and current injection technique guidance for your setting before administering a new or unfamiliar product.
Not checking the five rights before injection
The five rights of medication administration are the right patient, the right drug, the right dose, the right route, and the right time. Skipping or rushing through this check before any injection is a patient safety failure regardless of how routine the injection appears. Injection errors that cause patient harm, including wrong-dose and wrong-route events, are disproportionately associated with time pressure and the assumption that familiarity with the medication removes the need for verification.
The five rights check takes seconds when performed consistently. Establishing it as an unbreakable habit rather than a box-ticking exercise is the single most effective preparation step for any injecting practitioner.
Not expelling air from the syringe
Air in a syringe drawn up for injection should always be expelled before administration. For subcutaneous and intramuscular injections, a small air bubble in the syringe is not a direct safety risk but can displace a portion of the intended dose and create an air pocket at the injection site. For intravenous injection, air embolism is a serious safety risk and all air must be expelled before any IV administration. Draw up slightly more than the required dose, orient the needle upward, tap the syringe to bring air to the top, and expel the air and excess volume before confirming the dose.
During injection
Injection technique mistakes
Injecting into a contaminated or unclean site
All injection sites should be cleaned with an alcohol swab and allowed to dry completely before the needle is inserted. Inserting the needle before the alcohol has dried carries the alcohol into the tissue, which is unnecessarily painful and may interfere with local tissue response. Injecting into a site that has not been cleaned at all risks introducing cutaneous bacteria into deeper tissue, which is a preventable cause of injection site abscess.
The standard technique is to use a fresh alcohol swab, clean the site in a single outward spiral motion, and wait a minimum of 30 seconds for the alcohol to evaporate before inserting the needle. Do not blow on or fan the site to speed drying, as this recontaminates it.
Inserting at the wrong angle for the intended route
Angle of insertion determines the tissue layer reached by the needle tip. Subcutaneous injections require a 45 to 90 degree angle depending on the patient's subcutaneous tissue depth; a shallower angle risks intradermal delivery, which is inappropriate for most subcutaneous medications and is significantly more painful. Intramuscular injections require a 90 degree insertion angle to ensure the needle tip penetrates through the subcutaneous layer to the muscle. Intradermal injections require a 10 to 15 degree angle with the bevel up, and a correct intradermal injection produces a visible bleb under the skin.
Injecting too quickly
Forcing the plunger too rapidly increases the pressure in the tissue receiving the injection. Rapid injection causes more local pain and swelling, is associated with higher rates of injection site reactions for some medications, and for intramuscular injection can cause medication to track back along the needle path and deposit at an unintended tissue depth. A controlled, steady injection rate of approximately 10 seconds per millilitre is a commonly cited guideline for most subcutaneous and intramuscular injections. Follow product-specific guidance where it exists.
Not aspirating for IM injections when required
Aspiration before intramuscular injection, which involves drawing back the plunger briefly to check for blood before injecting, is a technique that has evolved significantly in clinical guidance. Current WHO and UK vaccination guidance for routine vaccines at standard sites does not recommend aspiration. However, aspiration remains appropriate when injecting into sites with higher vascular density or when clinical judgement identifies a specific risk of intravascular injection. Follow current guidance applicable to your specific product, route, and patient population.
After injection
Post-injection and sharps safety mistakes
Errors after the injection is complete cause a significant proportion of all needlestick injuries and injection site complications.
- Recapping needles by hand. Manual recapping is the most common mechanism of needlestick injury in injection settings. The needle cap should never be guided back onto the needle by hand. If recapping is necessary, use the single-hand scoop technique against a flat surface, or use a needle recapping device. For needles with integrated safety mechanisms, activate the mechanism immediately after withdrawal and dispose directly into the sharps bin.
- Massaging the injection site after subcutaneous injection. Massaging after subcutaneous injection disperses the medication from the intended depot, which alters the absorption profile. For medications such as insulin, low-molecular-weight heparin, and some biologics that depend on consistent subcutaneous absorption, massaging is a protocol error. Apply gentle pressure with a clean swab if needed to stop any minor bleeding, but do not rub or massage.
- Not documenting the injection correctly and immediately. Delayed or incomplete documentation creates a risk that a dose is omitted, repeated, or given at the wrong time. Document the medication, dose, route, site, time, and the patient identifier immediately after administration, before moving to the next patient or task. Retrospective documentation from memory is a patient safety risk.
- Not observing the patient after injection where required. Some medications require a post-injection observation period to detect immediate adverse reactions including anaphylaxis. The observation period and the required monitoring parameters are specified in the product licence or clinical protocol. Do not allow patients requiring post-injection observation to leave before the observation period is complete, regardless of how they appear to feel.
- Disposing of used needles in non-sharps waste. Used hypodermic needles must be disposed of in an approved sharps container immediately after use. Placing needles in clinical waste bags, in standard waste bins, or on trays or surfaces creates injury risk for all staff in the area and for waste management staff. The sharps bin should be accessible at the point of use so that disposal occurs in the same location as the injection.
Better equipment supports better technique
Hypodermic needles with safety mechanisms across all gauges
Charles Medical supplies safety-engineered hypodermic needles for clinical settings across the UK. Next-day delivery with no minimum order.
For a full guide to correct injection technique across all routes, see Hypodermic Needles for Injections: Techniques and Best Practice.
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This article is part of our complete hypodermic needle knowledge base, covering gauge selection, injection technique, medication compatibility, procurement, clinical applications, and safety across all settings from hospital wards to home use.
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Related guides in this hub
Hypodermic Needles for Injections: Techniques and Best Practice covers correct technique for each injection route in full. A Complete Guide to Hypodermic Needle Sizes and Gauges addresses the gauge and length selection errors that underpin many technique mistakes. And How to Choose the Right Hypodermic Needle for Medication Viscosity covers the specific challenges of viscous and difficult-to-administer medications.
Frequently asked
Injection technique questions answered
What is the most common injection technique error?
Incorrect angle of insertion is among the most common technique errors, as it can result in medication being deposited in the wrong tissue layer. Using the wrong gauge for the medication viscosity and not expelling air from the syringe are also frequent errors. In terms of patient safety impact, the failure to perform a five rights medication check before injection is the error most likely to result in a significant medication incident.
Should I massage the injection site after giving an injection?
It depends on the medication and route. Massaging after subcutaneous injection of medications that rely on consistent depot absorption, including insulin, low-molecular-weight heparin, and many biologics, alters the absorption profile and is a technique error. Apply gentle pressure with a clean swab to manage any minor bleeding but do not massage. Follow the specific technique guidance for the product being administered.
How long should I wait after cleaning the skin before injecting?
Allow a minimum of 30 seconds for the alcohol to evaporate completely before inserting the needle. Inserting into a wet alcohol-cleaned site carries the alcohol into the tissue, which is painful and may interfere with local response. Do not fan or blow on the site to speed drying as this recontaminates the cleaned area.
Can I use the same needle to draw up and administer a medication?
Technically yes, but drawing up through a vial stopper blunts the needle tip and increases patient discomfort during injection. For injections where minimising discomfort matters, draw up with one needle and replace with a fresh needle for administration. This is particularly relevant for fine gauge injections where even minor blunting significantly increases insertion resistance.
What should I do immediately after a needlestick injury?
Immediately wash the site thoroughly with soap and running water without scrubbing. Do not suck the wound. Cover with a waterproof dressing. Report the incident to your line manager and occupational health department immediately, following your organisation's post-exposure protocol. Do not delay reporting because the injury seems minor; post-exposure risk assessment and any indicated prophylaxis must be initiated promptly to be effective.