How To Lower Hematocrit For Plasma Donation

As a plasma donation expert running InterstateBloodbankChicago, I understand the importance of meeting eligibility criteria, including having a hematocrit level within the acceptable range. Donating plasma with high hematocrit can be challenging and even risky. This article will guide you through safe and effective ways to lower your hematocrit levels before your plasma donation appointment.

What is Hematocrit?

Hematocrit is a measure of the percentage of red blood cells in your total blood volume. Normal hematocrit levels range from 36-50% for women and 40-54% for men. However, plasma donation centers often require hematocrit levels below 50% for women and below 56% for men to ensure safe and efficient donation.

High hematocrit means a higher concentration of red blood cells, which can make your blood too viscous or thick for the plasma collection equipment. Donating with excessively high hematocrit levels can also lead to an unhealthy reduction in your red blood cell count, potentially causing anemia.

Why Check Hematocrit Before Donating Plasma?

Plasma donation centers check your hematocrit level before each donation for several reasons:

  • Blood Viscosity: High hematocrit means too many red blood cells, making your blood too thick or viscous for the collection machine to process efficiently.
  • Donation Safety: Donating with very high hematocrit levels can reduce your red blood cell count too much, potentially causing anemia or other health issues.
  • Donor Eligibility: Most plasma donation centers have specific hematocrit cutoff levels for donor eligibility to ensure a safe and successful donation process.

If your hematocrit level is above the accepted range, the staff at the plasma donation center may suggest ways to lower it or reschedule your appointment until your levels are within the acceptable range.

Safe Ways to Lower Hematocrit for Plasma Donation

If your hematocrit is too high, there are several safe and effective ways to lower it before your plasma donation appointment. Here are some tips:

1. Increase Fluid Intake

Drinking plenty of fluids is one of the most effective ways to lower your hematocrit levels. The recommended fluid intake is 3-4 liters of extra water daily for 2-3 days before your donation appointment. This extra hydration can help dilute your blood and lower the concentration of red blood cells, effectively reducing your hematocrit.

  • Drink water, coconut water, herbal teas, and diluted fruit juices.
  • Avoid alcohol and caffeinated beverages, as they can dehydrate you.
  • Spread your fluid intake throughout the day and drink slowly to prevent bloating.

2. Add Salt to Your Diet

Increasing your salt intake by 2-4 grams daily can help your body retain more fluids, effectively diluting your blood and lowering your hematocrit. However, be cautious with salt if you have hypertension or other medical conditions that require a low-sodium diet.

  • Focus on getting salt from natural sources, such as sea salt or salt-containing foods like soups, broths, and salted nuts.
  • Avoid processed foods with high sodium content, as they may have other unhealthy ingredients.

3. Eat Iron-Rich Foods

Consuming foods rich in iron can help lower your hematocrit levels. Iron is essential for the production of red blood cells, and by reducing your iron intake, you may decrease the production of new red blood cells, effectively lowering your hematocrit.

  • Leafy greens, beans, lentils, and lean red meat are good sources of iron.
  • Pair iron-rich foods with vitamin C-rich foods like citrus fruits, peppers, or tomatoes to enhance iron absorption.
  • Avoid iron supplements or iron pills, as excessive iron intake can raise your hematocrit.

4. Exercise Regularly

Regular exercise can help lower your hematocrit levels by increasing plasma volume and improving blood flow. Aim for 30 minutes of moderate exercise, such as brisk walking, most days. Strength training and High-Intensity Interval Training (HIIT) may also be effective in lowering hematocrit.

  • Drink extra fluids after exercising to replace lost water and maintain proper hydration.
  • Avoid intense exercise right before your donation appointment, as this can temporarily raise your hematocrit.

5. Give a Whole Blood Donation

If your hematocrit is significantly high, consider donating whole blood before your plasma donation appointment. Whole blood donation removes a significant number of red blood cells from your body, effectively lowering your hematocrit levels within a week.

  • Most people only need one whole blood donation before a plasma donation to lower their hematocrit.
  • Wait at least 8 weeks between whole blood and plasma donations to allow your body to recover and replenish its red blood cell supply.

6. Increase Time Between Donations

If your hematocrit levels are borderline high, increasing the time between your plasma donations can help your body rebalance its fluid levels and lower your hematocrit by 1-2% over time.

  • Aim to wait at least 8 weeks between plasma donations to allow your body to recover and maintain optimal hematocrit levels.

Safely Managing Hematocrit Levels

When attempting to lower your hematocrit levels, it’s important to do so safely and gradually. Here are some additional tips to keep in mind:

  • Changes in diet and hydration take 2-3 days to affect your hematocrit levels, so start making adjustments early before your donation appointment.
  • Aim for a moderate hematocrit reduction of 1-2% to avoid drastic changes that may negatively impact your health.
  • Avoid relying solely on supplements or medications to alter your hematocrit levels without medical supervision.
  • See your doctor immediately if you experience dehydration, dizziness, fatigue, or other concerning symptoms while trying to lower your hematocrit.
  • Discuss any chronic health issues or medications with your doctor before attempting to change your hematocrit levels, as some conditions or treatments may affect your body’s ability to regulate hematocrit.

Next Steps if Hematocrit Remains High

If lifestyle changes and dietary modifications don’t lower your hematocrit enough to meet the plasma donation center’s requirements, consult your doctor about medication options. Prescription diuretics like hydrochlorothiazide are commonly used to reduce hematocrit levels by 1-3%.

Your doctor may also check for underlying conditions such as sleep apnea, hypertension, or polycythemia vera (a blood disorder) that could contribute to high hematocrit levels. Proper treatment of these conditions can help normalize your hematocrit and make you eligible for plasma donation.


At InterstateBloodbankChicago, we understand the importance of meeting the eligibility criteria for plasma donation, including maintaining a healthy hematocrit level. By following the safe and effective tips outlined in this article, most healthy individuals can lower their hematocrit by 1-2% within a few days, often sufficient to qualify for donating plasma.

Remember, it’s crucial to make adjustments gradually and consult your doctor if you have any concerns or underlying health conditions. Monitoring your health and being an informed, responsible donor is key to keeping your hematocrit at optimal levels while contributing to the vital cause of plasma donation.

If you have any further questions or need assistance, our team at InterstateBloodbankChicago is always ready to provide guidance and support. Stay hydrated, make healthy choices, and keep donating!


Can you donate plasma if your hematocrit is high?


A high hematocrit could mean you are dehydrated (lack of body fluid). You may have to delay donating plasma.

What makes hematocrit go down?


Low hematocrit may be due to: Anemia. Bleeding. Bone marrow being unable to produce new red blood cells.

Does water lower hematocrit?


A steady intake of water increases hemoglobin indices, such as the MCH and MCHC, and decreases the MPV. As shown in Table 1, at the end of the study period, WBC, RBC, and platelet counts increased in the experimental group, as did hematocrit and hemoglobin levels, although the increases were not significant ( p >0.05).

How do you normalize low hematocrit levels?


To support the iron and hematocrit levels in your body, increase your intake of high iron foods. Eating foods rich in vitamin C such as citrus fruits, broccoli and tomatoes helps your body absorb the iron that you eat.

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