Muscle Insertional Activity on Electromyography
This electromyography (EMG) assessment evaluates electrical activity produced when a needle electrode is first inserted into a muscle. It is part of the EMG examination and is reported as a qualitative finding.
["Insertional activity is one component of a needle EMG study that can help evaluate muscle and nerve abnormalities."]
Key facts at a glance
- LOINC
- 98718-0
- Short code
- Insertional activity Muscle EMG
- Synonyms
- Insertional activity Muscle EMG
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Ref low
- 1.7
- Ref high
- 2.2
- Critical range
- 1 N/A – 5 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- emg
- CPT
- 83735
- Specimen volume
- 5 mL
- Stability
- Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 4–24 hours
- Order
- routine
What the test measures
During needle EMG, a small electrode is inserted through the skin into a selected muscle. The clinician observes the electrical response at insertion, while the muscle is at rest, and during activity.
How insertional activity is assessed
The response is interpreted as normal, increased, decreased, or otherwise abnormal based on its character and the clinical context. Interpretation considers the muscle examined, the technique used, and the other EMG findings.
Why the test may be performed
Needle EMG may be used to evaluate muscle weakness, numbness, tingling, pain, or suspected nerve or muscle disorders. Insertional activity is assessed along with spontaneous activity, motor-unit responses, and activation during contraction.
What to expect
The test is usually performed by a trained clinician and may require the patient to hold still, relax the muscle, and perform gentle movements. Mild soreness or bruising can occur afterward, but serious complications are uncommon.
Reference range
Adult: 1.7-2.2 mg/dLN/A
No special preparation usually required. Stay well hydrated. Inform your healthcare provider of all medications and supplements you are taking.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Abnormal insertional activity may be associated with muscle inflammation, injury, or certain nerve and muscle disorders, but it is not specific to one condition. Results should be interpreted by the clinician performing the EMG together with symptoms, examination findings, and other diagnostic tests.
Short name
Muscle insertional activity EMG
Frequently asked questions
Is this the same as a blood or urine test?
Does the test require medication changes?
Can a normal insertional response rule out a muscle or nerve disorder?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy