Yes, You Can Give a Subcutaneous Injection Wrong: Common Mistakes and How to Avoid Them

According to the Oncology Nursing Society, improper subcutaneous injection technique can lead to site reactions, sub-optimal medication absorption, and adverse events. Yes, it is possible to give a subcutaneous injection wrong, but with proper knowledge and technique, these risks can be minimized. This guide explains the common errors, their consequences, and how to perform a safe and effective self-injection.

Quick Summary

Several factors can lead to an incorrect subcutaneous injection, including wrong site selection, improper needle angle, and reusing equipment. Errors can cause pain, bruising, infection, and affect drug absorption, but proper technique and site rotation prevent these complications. This article details the common mistakes and provides guidance on performing a safe injection.

Key Points

• Proper Site Selection: Rotate injection sites (abdomen, thighs, upper arms) to prevent tissue damage and ensure consistent medication absorption.

• Use the Correct Angle: Insert the needle at a 90° angle for most individuals or a 45° angle if you have little body fat, as instructed by a healthcare provider.

• Maintain Sterility: Always use a new, sterile needle and syringe for each injection, and properly clean the site with an alcohol pad before injecting.

• Watch for Adverse Reactions: Be aware of signs like severe pain, spreading redness, swelling, or fever, which may indicate infection and require medical attention.

• Avoid Lipohypertrophy: Repeated injections in the same area can cause fatty lumps (lipohypertrophy), which can interfere with drug absorption.

• Wait Before Withdrawing: Prevent medication leakage by waiting several seconds after administering the full dose before removing the needle.

A subcutaneous (Sub-Q) injection is a common method for delivering medication into the fatty tissue just beneath the skin, also known as the subcutaneous layer. This route is preferred for drugs that need slow, steady absorption, such as insulin, blood thinners, and some fertility medications. While often performed by patients at home, errors in technique can occur, compromising the injection's effectiveness and potentially causing side effects. By understanding what can go wrong and how to practice correctly, patients can ensure their medication is administered safely.

What are the risks of giving a subcutaneous injection wrong?

Improper technique and site selection can lead to several complications, though serious injury is rare. The most common issues are localized, but others can impact the overall treatment effectiveness.

• Incorrect Injection Site: Administering the medication into an area with little fatty tissue, like over a bone or an area with bruising or scarring, can be painful and affect absorption. Injecting too close to the belly button or in an area with many nerve endings, like the inner thigh, can also cause pain. Repeatedly injecting into the same spot can cause lipohypertrophy—a firm, fatty lump that impedes proper medication absorption.
• Improper Needle Angle: Injecting at an incorrect angle can cause the medication to be delivered too shallowly into the skin's dermal layers or too deeply into the muscle. An injection that is too shallow can cause an injection site reaction (ISR), resulting in a red, sore, and itchy bump that can last for several days. An accidental intramuscular injection may alter the absorption rate of the drug. The correct angle depends on the amount of subcutaneous tissue present, with a 90° angle typically used for larger tissue folds and a 45° angle for thinner individuals.
• Poor Sterilization: Failing to clean the injection site with an alcohol swab and allow it to dry can introduce bacteria, leading to a local skin infection. Signs of infection can include increasing pain, swelling, warmth, and potentially pus or drainage.
• Reusing Needles: Needles should only be used once. Reusing needles increases the risk of infection, dulls the needle's sharpness, and can cause more pain and tissue damage.
• Leaking Medication: If medication leaks from the injection site, the full dose may not have been delivered. This can happen if the needle is removed too quickly. Waiting at least 5-10 seconds before withdrawal can prevent this.
• Injecting into a Blood Vessel: While rare in the subcutaneous layer, accidentally hitting a blood vessel can cause bruising and may alter the drug's absorption. You may see a small amount of blood after withdrawing the needle, but significant bleeding or blood in the syringe is a concern.

How to perform a correct subcutaneous injection

Following a precise, sterile technique is the most important step to prevent errors. Always follow the instructions from a healthcare provider or pharmacist.

1. Gather Supplies: Obtain your medication, a sterile syringe and needle, alcohol pads, and a sharps container.
2. Prepare the Medication: Check the medication for expiration date, proper appearance, and dosage. Allow refrigerated medication to reach room temperature to reduce pain.
3. Perform Hand Hygiene: Wash hands thoroughly with soap and water or use an alcohol-based sanitizer.
4. Select and Prepare the Site: Choose an appropriate injection site, such as the abdomen (at least 2 inches from the belly button), outer thigh, or outer upper arm. Avoid areas with bruising, scars, swelling, or lumps. Clean the site with an alcohol pad, wiping outwards from the center, and let it air dry completely.
5. Pinch the Skin: Gently pinch a 1 to 2-inch fold of skin between your thumb and forefinger to lift the subcutaneous tissue away from the muscle. This step is critical for proper delivery, especially for those with less body fat.
6. Inject at the Correct Angle: Insert the needle at a 90° angle for most individuals. If you have minimal fatty tissue, a 45° angle may be recommended by your provider. Insert the needle with a quick, firm motion.
7. Administer the Medication: Push the plunger slowly and steadily to inject the medication. Do not aspirate (pull back on the plunger).
8. Withdraw the Needle: After injecting the full dose, wait 5 to 10 seconds before quickly withdrawing the needle at the same angle it was inserted.
9. Apply Pressure: Place gauze or a cotton ball over the site and apply gentle pressure. Do not massage the area, as this can affect absorption.
10. Dispose of Sharps: Immediately dispose of the used needle and syringe in a designated sharps container.

Signs of a problem after injection

While most mild injection reactions are harmless, certain signs warrant contacting a healthcare provider immediately.

• Signs of localized infection: Increasing redness, warmth, swelling, pus, or severe pain at the injection site.
• Signs of cellulitis: Red streaks spreading from the injection site.
• Signs of systemic infection: Fever, muscle aches, or extreme tiredness.
• Severe pain or swelling: Pain that doesn't improve after 48 hours or swelling that worsens significantly.
• Significant bleeding: Bleeding that persists for more than 10 minutes.
• Allergic reaction: Hives, trouble breathing, or swelling of the face, lips, or tongue require emergency attention.
• Hard, painful lumps: Though some lumps (lipohypertrophy) are benign and resolve with site rotation, painful, persistent lumps should be checked.

Correct vs. Incorrect Subcutaneous Injection Techniques

Technique Aspect	Correct Procedure	Incorrect Procedure	Consequences of Error
Injection Site Selection	Rotating between abdomen, thighs, and upper arms; avoiding tender, scarred, or bruised areas.	Injecting in the same spot repeatedly or into a bruised area.	Lipohypertrophy (lumps), poor medication absorption, pain.
Needle Angle	90° angle for most, 45° for thin patients; inserting with a quick, firm motion.	Inserting too shallowly or too deeply; using a slow motion.	Injection site reactions, altered absorption, pain, bleeding.
Equipment Handling	Using a new, sterile needle and syringe for each injection.	Reusing a needle or handling it improperly before injection.	Increased risk of infection and tissue damage.
Post-Injection	Waiting 5-10 seconds before needle withdrawal; applying gentle pressure with gauze.	Withdrawing too quickly; massaging the injection site.	Medication leakage, poor absorption, bruising.
Sterilization	Cleaning the site with an alcohol pad and letting it air dry.	Not cleaning the site or not letting it dry.	Increased risk of skin infection.

Conclusion

While can you give a subcutaneous injection wrong is a valid concern, the majority of complications can be prevented by following proper technique, maintaining sterility, and diligently rotating injection sites. Knowing the correct procedure empowers patients to manage their health confidently and reduces the likelihood of discomfort, pain, and more serious complications like infection or poor medication absorption. Any significant adverse reactions or persistent issues should always be discussed with a healthcare provider.

For additional information on proper injection techniques, consult resources like the Centers for Disease Control and Prevention's guidelines for safe injection practices.

Frequently Asked Questions

What does a botched subcutaneous injection feel like?

An incorrectly administered subcutaneous injection can cause pain, stinging, and burning. You may also experience bruising, a small lump, or irritation at the site. Severe pain or spreading redness could indicate a more serious issue.

What happens if you inject subcutaneous medication into muscle?

Injecting subcutaneous medication into the muscle can alter the rate at which your body absorbs the drug. While usually not dangerous, it can affect the medication's effectiveness.

What should I do if I see blood in the syringe after injecting?

Seeing a small amount of blood after withdrawing the needle is typically normal. However, if you see blood in the syringe before or during the injection, remove the needle, discard the syringe, and start over with a fresh one.

What should I do if I get a lump after a subcutaneous injection?

Small, temporary lumps can be normal. If it is not red, warm, or painful, you can apply a warm compress. If the lump persists, gets larger, becomes painful, or shows signs of infection, contact your healthcare provider.

How do I know if the needle angle was wrong?

If the injection was too shallow, you may see a red, itchy bump (injection site reaction) that lasts a few days. If it was too deep into the muscle, the medication might absorb differently, and you might experience more significant pain or a faster-acting effect.

Can I get an infection from a wrong subcutaneous injection?

Yes, improper technique, such as failing to clean the injection site or reusing a needle, can lead to a skin infection or abscess. Seek medical attention if you notice signs of infection like fever, pus, or spreading redness.

Should I massage the injection site if it hurts?

No, you should not massage the site after a subcutaneous injection. Massaging can damage underlying tissue and cause the medication to absorb too quickly, affecting its intended slow release.