How It Feels
The blood sample is taken from a vein in
your arm. An elastic band is wrapped around your upper arm. It may feel tight.
You may feel nothing at all from the needle, or you may feel a quick sting or
There is very little chance of a problem from
having a blood sample taken from a vein.
- You may get a small bruise at the site. You
can lower the chance of bruising by keeping pressure on the site for several
- In rare cases, the vein may become swollen after the
blood sample is taken. This problem is called phlebitis. A warm compress can be
used several times a day to treat this.
- Ongoing bleeding can be a
problem for people with bleeding disorders. Aspirin, warfarin (Coumadin), and
other blood-thinning medicines can make bleeding more likely. If you have
bleeding or clotting problems, or if you take blood-thinning medicine, tell
your doctor before your blood sample is taken.
A renin assay blood test is done to find
the cause of
high blood pressure (hypertension). The time of day
and your position (standing, sitting, or lying down) before the blood sample is
collected, your age, and the level of sodium in your blood all affect the test
The normal values listed here—called a reference range—are just a guide. These ranges vary from lab to lab, and your lab may have a different range for what's normal. Your lab report should contain the range your lab uses. Also, your doctor will evaluate your results based on your health and other factors. This means that a value that falls outside the normal values listed here may still be normal for you or your lab.
Plasma renin activity
| Adult (upright
position, normal-sodium diet)
nanograms per milliliter per hour (ng/mL/hr) or
micrograms per liter per hour (mcg/L/hr)
|Adult (lying down, normal-sodium diet)
0.2–1.6 ng/mL/hr or 0.2–1.6
|Adult (upright position,
4.2–19.8 ng/mL/hr or 4.2–19.8
|Adult (lying down, low-sodium diet)
0.4–3.2 ng/mL/hr or 0.4–3.2