How To Lower Hematocrit Levels Safely For Plasma Donation


Matthew McClain

Plasma donation is an important way to help others in need. However, a high hematocrit level can make donating plasma difficult. This article provides tips on how to safely lower your hematocrit to qualify for donation.

What is Hematocrit?

Hematocrit measures the percentage of red blood cells in your total blood volume. Normal levels range from 36-50% for women and 40-54% for men. Donors require hematocrit under 50% for women and 56% for men.

Why Check Hematocrit Before Donating Plasma?

  • High hematocrit means too many red blood cells, requiring dilution before donation.
  • Very high levels make blood too viscous for the collection machine.
  • Donating with high hematocrit can reduce red blood cells too much, causing anemia.

Ways to Safely Lower Hematocrit

If your hematocrit is too high, here are safe ways to lower it:

1. Increase Fluid Intake

  • Drink 3-4 liters of extra water daily for 2-3 days before donation.
  • Avoid alcohol and caffeine, which dehydrate you.
  • Stick to water and hydrating drinks like coconut water, herbal tea, and diluted fruit juice.
  • Spread fluid intake throughout the day and drink slowly to prevent bloating.

2. Add Salt to Your Diet

  • Increase salt intake by 2-4 grams daily to help retain fluids.
  • Focus on getting salt through natural sources like sea salt rather than processed foods.
  • Be cautious with salt if you have hypertension or other medical conditions.

3. Eat Iron-Rich Foods

  • Leafy greens, beans, lentils, and lean red meat can help lower hematocrit.
  • Vitamin C helps with iron absorption, so pair iron-rich foods with citrus, peppers, or tomatoes.
  • Avoid supplements like iron pills, as excess iron raises hematocrit.

4. Exercise Regularly

  • Aim for 30 minutes of moderate exercise like brisk walking most days.
  • Strength training and High Intensity Interval Training (HIIT) may also help lower hematocrit.
  • Drink extra fluids after exercising to replace lost water.

5. Give a Whole Blood Donation

  • Donating whole blood removes red blood cells, lowering hematocrit significantly within a week.
  • Most people only need one whole blood donation before plasma donation.
  • Wait 8 weeks between whole blood and plasma donations.

6. Increase Time Between Donations

  • Waiting longer, ideally 8 weeks, between plasma donations allows fluid levels to rebalance.
  • This may lower borderline hematocrit by 1-2% over time.

Safely Managing Hematocrit Levels

  • Changes take 2-3 days to affect hematocrit, so start early before your donation.
  • Moderate hematocrit reduction by 1-2% is safe, but don’t overdo it.
  • Avoid relying on supplements to alter hematocrit without medical supervision.
  • See your doctor immediately if you experience dehydration, dizziness, fatigue, or other concerning symptoms.
  • Discuss any chronic health issues with your doctor before attempting to change hematocrit.

Next Steps if Hematocrit Remains High

If lifestyle changes don’t lower your hematocrit enough, ask your doctor about medication options. Prescription diuretics like hydrochlorothiazide are commonly used to reduce hematocrit by 1-3%.

Your doctor can also check for underlying conditions like sleep apnea, hypertension, or polycythemia vera that may contribute to high hematocrit. Proper treatment of medical issues helps normalize your levels.


With a few safe dietary and lifestyle changes, most healthy individuals can lower their hematocrit by 1-2% within a few days. This small reduction is often sufficient to qualify for donating plasma. However, it’s vital to make adjustments gradually and consult your doctor if you have any concerns. Monitoring your health and being an informed, responsible donor is key to keeping your hematocrit at optimal levels.

We hope this guide empowers you to safely manage your hematocrit for plasma donation. Please share any other tips that have worked for you in the comments! And don’t forget to talk to your doctor before making major changes to your diet or exercise routine.

2 thoughts on “How To Lower Hematocrit Levels Safely 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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