How To Lower Hematocrit For Plasma Donation?


Matthew McClain

Plasma donation is a safe and important procedure that involves the donation of plasma, the liquid part of blood. Plasma is used to make life-saving medications, such as clotting factors, antibodies, and albumin.

Hematocrit is the percentage of red blood cells in the blood. A high hematocrit can make it difficult to donate plasma, as the needle may not be able to draw enough blood.

What Is Hematocrit?

Hematocrit is the ratio of red blood cells to total blood volume. It’s measured by taking a blood sample and spinning it in a tube called a hematocrit tube. The percentage of red blood cells, known as the packed cell volume, is your hematocrit level.

A normal hematocrit range for men is 40% to 54% and women 36% to 48%.

For plasma or blood donors, hematocrit levels below 56% for men and 50% for women are required.

Why Is It Important To Check Hematocrit Levels Before Donating Plasma?

Hematocrit screening before plasma donation is vital because:

  1. High hematocrit indicates a concentrated blood supply with too many red blood cells, which needs to be diluted before donation.
  2. Very high hematocrit levels can make blood too viscous for the collection machine and affect centrifugal separation of plasma.
  3. Donating plasma with hematocrit above limits can reduce donors’ red blood cell volume too much, potentially causing anemia.

Ways To Lower Hematocrit Levels

If your hematocrit level is too high for plasma donation, here are “Top 8 Ways To Lower Your Hematocrit For Plasma Donation”:

1. Drink More Fluids

Increasing fluid intake, mainly water, for a few days before donation can dilute the red blood cells in your blood and lower hematocrit. Aiming for 3 to 4 liters (10-14 cups) of extra water per day is recommended.

Avoid alcohol and caffeine. These substances can dehydrate you, which can raise your hematocrit.

2. Increase Salt Intake

Adding some extra salt to your diet, around 2 to 4 grams per day, can trigger your body to retain more water. This also helps dilute your blood and slightly lower hematocrit.

3. Donate Whole Blood First

Giving a whole blood donation, which removes red cells along with plasma, is a fast and effective way to reduce your hematocrit significantly within about a week. Most donors need just one standard whole blood donation to lower hematocrit enough for plasma.

4. Wait Longer Between Donations

Giving your body more time, 4 to 8 weeks, between plasma donations can allow your body to naturally produce more fluids and dilute your blood slightly. This may help borderline hematocrit levels dip below the required limit.

5. Eat More Fiber

Dietary fiber, found in fruits, vegetables and whole grains, can increase water retention in your body. Adding more high-fiber foods in the weeks before donation may help lower your hematocrit a percentage point or two.

6. Exercise regularly

Exercise can help to increase blood flow and lower your hematocrit. Aim for at least 30 minutes of moderate-intensity exercise most days of the week.

7. Don’t live in high places

If your home is 2,000 meters above sea level, it is thought to boost hematocrit levels in the blood because the bone marrow creates more red blood cells to make up for the lower oxygen levels in these areas. To avoid this, stay in low-lying locations.

8. See the doctor

If you are unable to lower your hematocrit naturally, your doctor may prescribe a medication to help. Prescription diuretics are the most common medication used to lower hematocrit. Diuretics work by increasing urination, which helps to remove excess fluids from the body. Over-the-counter diuretics, such as caffeine and alcohol, can also help to lower hematocrit.

If you have a high hematocrit, it is important to see a doctor. A high hematocrit can be a sign of a more serious medical condition, such as polycythemia vera. Your doctor will be able to assess your risk factors and determine the best course of treatment.

In summary, hematocrit screening is an important safety check for plasma donors to ensure their red blood cell volume remains at a healthy level. If your hematocrit is too high, there are a few strategies you can use to lower it enough to qualify for plasma donation.

Giving a whole blood donation first is the most effective and fastest way to significantly reduce your hematocrit. Other options like increasing fluids, salt and fiber intake and waiting longer between donations can also help lower your hematocrit by a few percentage points.

But the key is to start these strategies well before your scheduled donation to give them time to work. Staying hydrated right up until donating also helps ensure your blood is properly diluted.

If you have any concerns about your hematocrit level or need assistance lowering it, be sure to discuss your options with the medical staff at your local plasma donation center. With the proper guidance and screening, most donors with high hematocrit can make adjustments to qualify for safe and successful plasma donations.

So check your hematocrit level as required for your next donation and take appropriate steps to lower it if needed. Communication with the medical personnel will also help ensure you maintain a healthy balance between donating plasma and maintaining your normal red blood cell volume.


1. Can I donate plasma if my hematocrit is 55?

For safety, most donation centers require hematocrit under 56 for men and 50 for women. You may need to take steps to reduce your hematocrit a few points before donating.

2. How long does it take for fluid loading to lower hematocrit?

Increasing fluid intake for 2 to 3 days is often enough to dilute your red blood cells and lower your hematocrit level by 1% to 2%. But clear fluids pass through your system quickly, so steady hydration before and right up to donation is ideal.

3. What is the easiest way to lower hematocrit fast?

The fastest and most reliable way is to give a whole blood donation, which directly removes red blood cells and reduces hematocrit by 7% to 10%. Increasing fluids and waiting longer between donations also typically provide at least a 1% to 2% drop after a few days.

1 thought on “How To Lower Hematocrit For Plasma Donation?”

  1. Yeah your “donating whioe blood before”, doesn’t work because you are ineligible/deferred for 60 days tfrom donating plasma, after donating rbc. And, In 2 months, you’ve already built more rbc supply so you’ve undone what you set out to do.


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