Serum or Plasma Free Angiotensin II Concentration
This test measures the amount of a hormone called angiotensin II that is present in your blood without being bound to proteins.
["Assessing free angiotensin II helps evaluate blood pressure regulation and kidney function."]
Key facts at a glance
- LOINC
- 27364-9
- Short code
- ASPNAB
- Synonyms
- A niger Ab Fld Ql ID
- Category
- chemistry
- Sample
- serum
- Container
- Serum separator tube (SST) or red-top vacuum tube without anticoagulant; sterile screw-cap transport vial if aliquoting
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- ≥ 0 years
- Method
- immune-diffusion
- CPT
- 86606
- SNOMED
- 39507000
- Specimen volume
- 1-2 mL serum (minimum 0.5 mL); 5-10 mL whole blood collected in SST
- Stability
- Serum stable at room temperature for 8 hours; refrigerated (2-8°C) for up to 7 days; frozen at -20°C or below for up to 30 days. Avoid repeated freeze-thaw cycles.
- 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 suspected conditions affecting your blood pressure, kidney function, or hormone-related disorders. It could also be part of a broader evaluation for conditions like hypertension, kidney disease, or certain endocrine disorders.
What to Expect Before the Test
No special preparation is typically required, but you may be asked to fast for a few hours before the blood draw if your test involves fasting samples. Avoid smoking or consuming caffeine for 30 minutes before testing to minimize interference.
What Happens During the Test
A healthcare professional will collect a blood sample from a vein in your arm. The blood will be processed to separate the serum or plasma, which is then analyzed for angiotensin II levels using a specialized immunoassay method.
What the Results Mean
Results are interpreted based on clinical context and individual health status. Elevated levels may suggest conditions like hypertension or kidney dysfunction, while lower levels might indicate hormonal imbalances or other metabolic issues. Your doctor will discuss these findings with you.
Reference range
Negative: No precipitin bands detected. Positive: One or more precipitin bands observed indicating presence of Aspergillus niger-specific IgG antibodies. Titers may be reported semi-quantitatively.N/A
No special preparation required. Fasting is not necessary. Patients on antifungal therapy may have reduced antibody titers; document recent or current antifungal use on requisition.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
Free Angiotensin II
Frequently asked questions
Angiotensin II is a potent vasoconstrictor that plays a key role in regulating blood pressure and fluid balance. Free angiotensin II levels can reflect how effectively your body is managing these processes. Abnormal results may prompt further evaluation for conditions like renal artery stenosis, endocrine disorders, or cardiovascular disease.
Results are typically available within 1 to 3 business days, depending on your lab’s processing schedule. Your healthcare provider will contact you directly with the results once they are ready.
Most tests do not require fasting, but follow any specific instructions your healthcare provider gives you. If fasting is required, avoid solid foods for 8–12 hours before the test and liquids (except water) for 4–6 hours.
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