Blood Test: What It Is, Why It Is Done, and What to Expect During Your Laboratory Blood Draw
A blood test that measures the level of Angiotensin II in your blood while lying down, helping doctors evaluate conditions related to blood pressure and kidney function.
{"Angiotensin II is a hormone that helps control blood pressure and fluid balance","The test requires lying still for 30-60 minutes before blood is drawn","It helps diagnose conditions like hypertension, kidney disease, and adrenal disorders","Results are often compared with standing test results for better diagnosis","Certain medications may need to be stopped before the test"}
Key facts at a glance
- LOINC
- 70074-0
- Short code
- ANGII-S
- Synonyms
- Angiotensin II sup Plas-mCnc
- Category
- chemistry
- Sample
- plasma
- Container
- Pre-chilled lavender-top (EDTA) tube or pre-chilled vacuum tube with EDTA; alternatively, pre-chilled EDTA tube with aprotinin (protease inhibitor)
- Units
- N/A
- Ref low
- 10
- Ref high
- 30
- Critical range
- — – 100 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–99 years
- Method
- Radioimmunoassay (RIA) or Chemiluminescent Immunoassay (CLIA)
- CPT
- 82164
- SNOMED
- 14728009
- Specimen volume
- 3-5 mL of whole blood (minimum 1.5 mL plasma)
- Stability
- Plasma separated immediately and frozen at -20°C or below; stable for 1 month at -20°C; stable for 6 months at -80°C; avoid repeated freeze-thaw cycles
- Hemolysis max
- 100
- Lipemia max
- 300
- Icterus max
- 20
- TAT
- 24–96 hours
- Order
- routine
What is this test? A blood test is a common laboratory procedure in which a small sample of your blood is drawn, usually from a vein in your arm, and then analyzed to check your overall health, screen for medical conditions, or monitor a diagnosis you already have.
The Angiotensin II test measures the amount of a hormone called Angiotensin II in your blood. Angiotensin II is a key part of the renin-angiotensin-aldosterone system (RAAS), which plays a crucial role in regulating blood pressure, blood volume, and fluid balance in your body. The 'supine' part means you will be lying down during the test.
Why is it performed? Your doctor may order a blood test to help diagnose infections, anemia, diabetes, thyroid problems, or other conditions, to screen for diseases before symptoms appear, or to track how well a medication or treatment plan is working over time.
This test helps doctors evaluate: High blood pressure (hypertension), Kidney function and blood flow to the kidneys, Adrenal gland disorders, Conditions that affect the RAAS system, and sometimes to monitor the effectiveness of certain blood pressure medications.
How to prepare for the test: In most cases only minimal preparation is needed. Your doctor will tell you if you must fast for 8 to 12 hours beforehand, drink extra water, or temporarily stop certain medications or supplements, so follow those instructions carefully before your appointment.
Before the test, you may need to: Fast (not eat or drink) for 8-12 hours, Avoid certain medications like ACE inhibitors, beta-blockers, or diuretics as directed by your doctor, Rest in a lying down position for 30-60 minutes before blood is drawn, Inform your doctor about all medications and supplements you are taking.
What happens during the test? A trained technician wraps a band around your upper arm, cleans the skin with an antiseptic, and inserts a small needle into a vein to collect one or more tubes of blood; the procedure usually takes less than ten minutes and causes only brief discomfort.
A healthcare professional will first have you lie down comfortably for 30-60 minutes to establish a baseline. Then, a blood sample will be taken from a vein in your arm using a small needle. The sample is sent to a laboratory for analysis. The entire process usually takes less than 10 minutes.
Are there any risks? Serious problems are rare. You may feel a quick sting when the needle goes in, and mild bruising, soreness, or slight bleeding at the puncture site can occur; these effects normally fade within a few days, but contact your doctor if swelling or pain worsens.
The risks are minimal and similar to any routine blood test, including slight pain or bruising at the injection site, lightheadedness, and in rare cases, infection. These risks are generally very low.
Reference range
Supine: 10-30 pg/mL (approximately 10-60 pg/mL depending on assay); values vary by laboratory method and reference populationN/A
Patient should maintain supine position for at least 30 minutes prior to specimen collection. Avoid excessive salt intake or salt restriction for 3 days prior. Avoid diuretics, ACE inhibitors, ARBs, beta-blockers, and NSAIDs for 2 weeks if possible (consult physician). Avoid strenuous exercise before testing.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Elevated Angiotensin II levels may indicate conditions such as renovascular hypertension (high blood pressure due to kidney artery narrowing), congestive heart failure, adrenal insufficiency, or certain kidney disorders. Low levels may be associated with adrenal tumor (Conn's syndrome), certain kidney diseases, or inappropriate medication effects. The supine position test is often compared with a standing test to better understand how your body responds to posture changes, which can provide more accurate diagnostic information.
Frequently asked questions
How long does it take to get results?
Do I need to stop my blood pressure medications before the test?
Why do I need to lie down before the test?
Is the test painful?
Can I eat or drink before the test?
Sources
- 1
- 2
- 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 15, 2026. · Read our editorial policy