Cyclin-dependent kinase 4 (CDK4) activity in serum/plasma
This test measures the activity level of Cyclin-dependent kinase 4 (CDK4), an enzyme involved in cell cycle regulation. It may be used to assess abnormal cell growth or progression in certain conditions.
["CDK4 activity helps evaluate potential genetic or cellular abnormalities that could affect how cells grow and divide."]
Key facts at a glance
- LOINC
- 96270-4
- Short code
- CDK4-IHC
- Synonyms
- CDK4 Ag Ca spec Ql ImStn
- Category
- chemistry
- Sample
- serum
- Container
- Cancer tissue specimen in 10% neutral buffered formalin (NBF); paraffin-embedded tissue block (FFPE) or unstained tissue sections mounted on positively charged glass slides
- Units
- N/A
- Ref low
- 0
- Ref high
- 3
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- immune-stain
- CPT
- 88341
- SNOMED
- 250441005
- Specimen volume
- Tissue block or 4-5 unstained formalin-fixed paraffin-embedded (FFPE) tissue sections (3-4 μm thick) on charged slides; minimum representative tumor area required
- Stability
- FFPE tissue blocks: stable indefinitely at room temperature. Unstained slides: stable for up to 6 months at 2-8°C. Fresh tissue must be fixed in 10% NBF within 1-2 hours of collection and fixed for 6-72 hours depending on tissue thickness.
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 48–168 hours
- Order
- routine
Why This Test Might Be Ordered
Your healthcare provider may recommend this test if you have symptoms or a history suggesting conditions like certain cancers (e.g., sarcoma), genetic disorders affecting cell division, or other suspected abnormalities in cell cycle regulation. It could also be part of a broader diagnostic workup for unexplained growths or genetic testing.
How the Test Works
The test analyzes the functional activity of CDK4 in your blood sample. This involves detecting the enzyme’s ability to catalyze specific biochemical reactions tied to its role in cell cycle progression. The results help determine whether CDK4 is functioning normally or if there are signs of altered activity.
Sample Collection and Preparation
A blood sample is drawn, typically from a vein in your arm. The sample is processed to separate serum or plasma, which is then analyzed for CDK4 activity. This process ensures accurate measurement of the enzyme’s presence and function.
Interpreting Your Results
Interpretation of CDK4 activity results depends on clinical context and comparison with known reference ranges for healthy individuals. Elevated or altered activity may indicate conditions requiring further investigation, such as genetic mutations or cancer-related changes.
Reference range
Interpreted qualitatively by pathologist. Negative (no nuclear staining or staining in <1% of tumor cells) is considered normal/absence of CDK4 overexpression. Positive (nuclear staining in ≥1% of tumor cells) indicates CDK4 antigen presence. Scoring systems (e.g., H-score, percentage of positive cells, staining intensity 0-3+) may be used depending on institutional protocol.N/A
No special patient preparation is required prior to specimen collection. However, this test is performed on tissue/cancer specimens obtained via biopsy or surgical resection, not peripheral blood. Proper fixation and handling of tissue specimen is critical for accurate results.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
CDK4 is a critical regulator of cell division. Abnormal CDK4 activity may be linked to conditions like certain cancers (e.g., leiomyosarcoma), genetic syndromes affecting cell growth, or other disorders where uncontrolled cell proliferation occurs. While not all abnormal results will lead to a diagnosis, they may prompt additional testing or monitoring.
Short name
CDK4 Activity
Frequently asked questions
What does a CDK4 activity test measure?
How is the blood sample prepared for this test?
Can CDK4 activity test results be affected by diet or medications?
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.
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Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy