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Learn about your fainting after giving or seeing blood, including causes and common questions. Or get a personalized analysis of your fainting after giving or seeing blood from our A.I. health assistant. At Buoy, we build tools that help you know what’s wrong right now and how to get the right care.

Fainting After Giving or Seeing Blood Checker

Take a quiz to find out why you’re having fainting after giving or seeing blood.

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Your Fainting After Giving or Seeing Blood May Also be Known as:
Fainting when giving blood
Fainting when seeing blood
Passing out when giving blood
Passing out when seeing blood

Top 10 Fainting After Giving or Seeing Blood Causes

  1. 1.Long Fainting Episode

    Fainting for an extending period of time requires an immediate physician work-up because it could be serious. You should see a doctor immediately.

    There may be several explanations for this symptom and its severity, but a healthcare professional should make an assessment as soon as possible because it may be serious.

    Rarity:
    Uncommon
    Top Symptoms:
    long fainting episode
    Urgency:
    Emergency medical service
  2. 2.Chronic Carbon Monoxide Poisoning

    Chronic carbon monoxide poisoning is the slow but persistent exposure to carbon dioxide, typically where one lives or works. This can cause chronic headache, nausea, vomiting, etc.

    You should visit your primary care physician within the next 48 hours, who can make a diagnosis based on clinical suspicion and a blood test. Treatment would be to move away from the source of the carbon monoxide!

    Rarity:
    Rare
    Top Symptoms:
    fatigue, headache, irritability, nausea, difficulty concentrating
    Urgency:
    Primary care doctor
  3. 3.Low Blood Sodium

    Hyponatremia is a deficiency in sodium. Sodium is one of the most important nutrients in the body, needed for nerves to conduct signals, muscles to contract, and blood pressure to be maintained at safe levels, etc. A deficiency in sodium can cause severe, widespread symptoms.

    You need to seek care immediately. A walk-in clinic will likely be able to help bring your sodium levels back up to normal levels safely.

    Rarity:
    Rare
    Top Symptoms:
    fatigue, nausea, headache, abdominal pain (stomach ache), loss of appetite
    Urgency:
    In-person visit
  4. 4.Atrial Fibrillation

    An arrhythmia is a problem with the speed or rhythm of the heartbeat. The atria comprise two out of the four chambers of the heart. When their beat is disturbed, symptoms such as a racing heart, chest pain, breathlessness, and dizziness may occur.

    Call 911 immediately for an ambulance. The symptoms of atrial fibrillation can be hard to distinguish from a heart attack, so better be safe.

    Rarity:
    Rare
    Top Symptoms:
    fatigue, shortness of breath, chest pain, racing heart beat, lightheadedness
    Urgency:
    Emergency medical service
  5. 5.Gonococcal Cervicitis

    Gonorrhea is a common STD and 350,000 cases occur each year in the United States. It is transmitted through unprotected sex.

    You should visit your primary care physician to get tested as soon as possible and discuss treatment options. Please make sure you have protected intercourse until you have been tested.

    Rarity:
    Uncommon
    Top Symptoms:
    vaginal discharge, vaginal bleeding, painful sex, yellow pus vaginal discharge, heavy menstrual flow
    Symptoms that never occur with gonococcal cervicitis:
    improving vaginal discharge
    Urgency:
    Primary care doctor

    Fainting After Giving or Seeing Blood Checker

    Take a quiz to find out why you’re having fainting after giving or seeing blood.

    Take a quiz
  6. 6.Condition Involving Blue Skin

    Blue skin may be due to a lack of oxygen delivered to that area by the blood, which is dangerous. You should see a doctor immediately!

    There may be several explanations for this symptom and its severity, but a healthcare professional should make an assessment as soon as possible because it may be serious.

    Rarity:
    Uncommon
    Top Symptoms:
    blue skin
    Urgency:
    Emergency medical service
  7. 7.Foot Weakness

    Any foot weakness is a sign of nerve damage, which is very worrisome and requires you to go see a doctor immediately!

    There may be several explanations for this symptom and its severity, but a healthcare professional should make an assessment as soon as possible because it may be serious.

    Rarity:
    Uncommon
    Top Symptoms:
    foot weakness, lower leg weakness, severe pelvis pain, arm weakness
    Urgency:
    Hospital emergency room
  8. 8.Atrial Flutter

    Atrial fibrillation or flutter is a common type of abnormal heartbeat. The heart rhythm is fast and irregular in this condition.

    You should visit your primary care physician within the next 24 hours. Your doctor will examine your heartbeat with an ECG (electrocardiogram) to confirm the diagnosis. Prescription medication is available to return the heart rhythm back to normal.

    Rarity:
    Common
    Top Symptoms:
    shortness of breath, racing heart beat, lightheadedness, deep chest pain, behind the breast bone, shortness of breath on exertion
    Urgency:
    In-person visit
  9. 9.Vasovagal Syncope

    Vasovagal syncope is one of the most common causes of fainting. Vasovagal syncope occurs when the body overreacts to certain triggers, such as the sight of blood or extreme emotional distress. The body coordinates a sudden drop of heart rate and blood pressure, causing reduced blood flow to the brain and a brief loss of consciousness.

    You do not need immediate treatment for this condition, as it is normal and not a cause for concern. However, since it has been going on for a while, you may want to discuss the fainting episodes with your doctor over the phone to discuss if any intervention is needed. You may require medical attention if during the fainting episode you fell and injured a body part.

    Rarity:
    Common
    Top Symptoms:
    lightheadedness, brief fainting episode, having fainted multiple times, fainting after standing for a long time, fainting episode after a specific trigger
    Symptoms that always occur with vasovagal syncope:
    brief fainting episode, having fainted multiple times
    Symptoms that never occur with vasovagal syncope:
    feeling completely normal before fainting
    Urgency:
    Phone call or in-person visit
  10. 10.Acute Carbon Monoxide Poisoning

    Carbon monoxide (CO) is a gas that has no odor or color. But it is very dangerous. It can cause sudden illness and death. CO is found in combustion fumes, such as those made by cars and trucks, lanterns, stoves, gas ranges and heating systems. CO from these fumes can build up in places that don't have a good flow of fresh air. One can be poisoned by breathing them in.

    Call 911 immediately. Carbon monoxide poisoning is diagnosed using a blood test but treatment can begin with high clinical suspicion. Treatment involves high-flow oxygen therapy and close monitoring.

    Rarity:
    Rare
    Top Symptoms:
    fatigue, nausea, headache, shortness of breath, vomiting
    Symptoms that never occur with acute carbon monoxide poisoning:
    fever
    Urgency:
    Emergency medical service

Questions Your Doctor May Ask About Fainting After Giving or Seeing Blood

  • Q.If this interview is about someone else, or "myself" is selected by accident, it is very important for us not to miss this question: has the person regained consciousness?
  • Q.How long were you unconscious?
  • Q.Have you been feeling more tired than usual, lethargic or fatigued despite sleeping a normal amount?
  • Q.Do you notice your heart beating hard, rapidly, or irregularly (also called palpitations)?

If you've answered yes to one or more of these questions, check our fainting after giving or seeing blood symptom checker.

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Fainting After Giving or Seeing Blood Symptom Checker Statistics

  • People who have experienced fainting after giving or seeing blood have also experienced:

    • 9% Hearing Loss
    • 9% Fatigue
    • 4% Watery Eye Discharge
  • People who have experienced fainting after giving or seeing blood were most often matched with:

    • 21% Long Fainting Episode
    • 15% Chronic Carbon Monoxide Poisoning
    • 10% Low Blood Sodium

Fainting After Giving or Seeing Blood Checker

Take a quiz to find out why you’re having fainting after giving or seeing blood.

Take a quiz