Complement Factor H (CFH) – Serum or Plasma Concentration
This test measures the amount of Complement Factor H, a protein that helps regulate the immune system’s complement pathway, which protects cells from damage.
["CFH helps maintain balance in your immune response and may be checked if you have symptoms of immune-related conditions."]
Key facts at a glance
- LOINC
- 47014-6
- Short code
- CD21IHC
- Synonyms
- CD21 Ag Tiss Ql ImStn
- Category
- chemistry
- Sample
- serum
- Container
- Tissue biopsy in 10% neutral buffered formalin (NBF); serum (if applicable) in serum separator tube (SST) or red-top tube.
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- ≥ 0 years
- Method
- immune-stain
- CPT
- 88342
- SNOMED
- 446131000124105
- Specimen volume
- Tissue: adequate biopsy size (minimum 0.5 cm³ recommended for adequate representation); Serum: 1-2 mL.
- Stability
- Tissue in formalin: stable for 24-72 hours at room temperature (15-25°C); formalin-fixed paraffin-embedded blocks stable indefinitely at room temperature. Serum: stable for 7 days at 2-8°C, 30 days at -20°C.
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 24–72 hours
- Order
- routine
Why This Test Is Done
Your doctor may order this test if you have symptoms like vision changes, kidney problems, or skin rashes that could be linked to an overactive or imbalanced immune response. It may also be part of evaluating conditions such as age-related macular degeneration (AMD) or hereditary angioedema.
What to Expect Before the Test
No special preparation is needed. You may have a blood sample drawn from a vein in your arm, or if testing urine, you’ll collect a sample at home or during a scheduled visit. Avoid alcohol or certain medications for 24 hours before testing if instructed.
What the Results Mean
Results are interpreted by your healthcare provider based on your medical history and symptoms. Abnormal levels may indicate conditions affecting immune regulation or specific genetic disorders.
Common Conditions Linked to CFH Levels
Elevated levels might be seen in certain immune disorders, while low levels could be associated with conditions like hereditary angioedema or autoimmune diseases. Always discuss results with your doctor.
Reference range
Reported as Positive (present) or Negative (absent) for CD21 antigen expression in tissue. Positive staining is characterized by membranous and/or cytoplasmic reactivity in follicular dendritic cells, B-lymphocytes, and selected epithelial/immune cell populations. Results interpreted by pathologist in clinical and morphologic context.N/A
No special patient preparation required prior to tissue biopsy or surgical specimen collection. For serum specimens (if concurrently ordered), no fasting is necessary.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
CFH Level
Frequently asked questions
What causes abnormal CFH levels?
How long does it take to get results?
Can diet or supplements affect CFH levels?
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