Febrile Non Hemolytic Transfusion Reaction

Overview

A febrile non-hemolytic transfusion reaction (FNHTR) is a fever that happens during a blood transfusion or soon after it ends. 'Febrile' means fever. 'Non-hemolytic' means the transfused red blood cells are not being destroyed — so this is not the dangerous kind of reaction. It is caused by your body reacting to small parts of the donated blood, such as leftover white cells or substances that build up while blood is stored. It is uncomfortable, but it is usually mild and settles down on its own.

Yes, it is common. It is the reaction doctors see most often during blood transfusions. Exact numbers vary, but it happens in a small number of transfusions — often estimated at around 1 in 100, and it is even more common with platelet transfusions (transfusions of the cells that help blood clot).

It can affect anyone who receives blood or blood products. It is more likely in people who have had many transfusions before, people who have had a reaction to a transfusion in the past, and people receiving platelets rather than red blood cells. It can happen at any age, including in children and older adults.

Symptoms

Common symptoms

• A rise in temperature — often a fever of 38°C (100.4°F) or more, or at least 1°C above your normal temperature
• Chills and shivering, sometimes with full-body shaking (rigors)
• Feeling hot, then cold, and unable to get warm
• Headache
• Feeling sick or being sick
• A mild ache in the back or chest
• Feeling restless, anxious or generally unwell
• A faster heartbeat

Symptoms in children

• Feeling hot to the touch, or a raised temperature on a thermometer
• Shivering, or being wrapped up and still cold
• Being fussy, clingy or hard to settle
• Crying more than usual, or being unusually quiet and sleepy
• Not feeding or drinking as well as usual
• Looking pale or blotchy

Symptoms in older adults

• Sometimes no high fever at all — older adults may not mount much of a temperature
• Feeling confused, muddled or 'not themselves'
• Feeling suddenly weak, dizzy or unsteady on their feet
• A fast heartbeat or feeling breathless
• Generally feeling unwell without being able to say why

Causes

Main causes

• Substances called cytokines (chemical messengers) that build up in stored blood and trigger a fever when they enter your body
• Antibodies in your blood reacting to white cells or platelets left in the donated blood
• A mild immune 'alert' reaction to proteins or cell fragments in the donated unit

Risk factors

• Having had a transfusion reaction before
• Having received many transfusions over time
• Receiving platelets rather than red blood cells
• Having had a pregnancy in the past (which can create antibodies to white cells)
• Receiving blood that has not been filtered to remove white cells

When to see a doctor

See a doctor urgently if:

• Any fever, chills or shivering during a transfusion or in the 24 hours after one — tell the nurse or doctor straight away, even if you feel it is minor
• Feeling very unwell with a headache, sickness or back pain after a transfusion
• A rash, itching or swelling after a transfusion
• Dark or reduced urine (pee), or feeling unusually thirsty and unwell, after a transfusion

Book a routine appointment if:

• A mild reaction that has settled, but you want to talk it through with your care team
• You are due another transfusion and are worried about a reaction happening again — ask about planning ahead
• You have questions about what happened during a previous transfusion

Diagnosis

Doctors recognise this reaction mainly by what happens and when. If you develop a fever or chills during or shortly after a transfusion, the team will stop or slow the transfusion and check you over. The key job is to make sure it is not a more serious type of reaction, such as one where blood cells are being destroyed, an allergic reaction, an infection, or a lung problem. They do this by examining you, asking how you feel, and running some blood and urine tests. The diagnosis of a febrile non-hemolytic reaction is usually made once these more serious causes have been ruled out.

Tests that may be done

• Checking your temperature, blood pressure, pulse, breathing rate and oxygen level
• Comparing the labels on the blood unit with your details, to confirm the right blood was given
• Blood tests to look for signs that red blood cells are being broken down, such as bilirubin and a blood count
• A urine test to check for blood or breakdown products in your pee
• A blood test called a direct antiglobulin test, which looks for antibodies stuck to your red cells
• Blood cultures (a test for infection) if your team suspects an infection rather than a transfusion reaction
• A chest X-ray if you have breathing problems

What to expect at your appointment

The checks usually happen straight away, at your bedside and in the lab. Some results come back within minutes to hours, while blood cultures can take a day or more. You will be monitored closely in the meantime. Most people find their temperature settles within a few hours, and the tests are mainly to confirm there is nothing more serious going on.

Treatment

The first step is always to stop or slow the transfusion and let your care team assess you. In most cases the fever settles on its own with rest, fluids, and keeping you comfortable. Any further transfusion is only restarted once your team is sure it is safe, and often a different approach is used for future transfusions.

Self-care at home

• Tell your nurse or doctor immediately if you feel hot, cold, shivery or unwell during a transfusion — do not wait it out
• Once home, rest and drink plenty of fluids
• Take your temperature if you feel feverish, and note the reading and the time
• Keep a note of when your transfusion was and how you felt afterwards, so you can tell your care team
• Follow any advice your transfusion team gives you about what to look out for in the next 24 hours

Medical treatments

Your team will stop or slow the transfusion and check your temperature, pulse, blood pressure and breathing. They may give you a medicine to bring your temperature down and ease discomfort, and fluids if you need them. If you are shivering badly, they will keep you warm and comfortable. The transfusion may be restarted slowly if the team is confident it is safe, or a different blood product may be used. For future transfusions, your team might use blood that has been filtered to remove white cells, or 'washed' blood products, and may take extra steps before the transfusion starts. Everything is decided case by case by your clinical team.

When is surgery considered?

Surgery is not part of treating this reaction.

Living with this condition

Most people feel back to normal within a day or so. If you need transfusions regularly — for example for a long-term blood condition — it helps to know what your own early warning signs feel like. Tell the staff at the very first hint of feeling hot, cold or shivery. Many transfusion units keep a record of reactions so the team can plan ahead for your next one.

Lifestyle tips

• Carry a card or note, or use your phone, to record that you have had a transfusion reaction and what happened
• Tell any new doctor, nurse or dentist about your transfusion history
• Plan a little rest time after a transfusion, especially if you have felt unwell after one before
• Eat and drink normally, and keep well hydrated before and after a transfusion

Diet and exercise

There is no special diet for this reaction. Eating normally and drinking enough fluids helps you feel better and recover faster. Gentle activity is fine once you feel well again. If you have another health condition that affects your diet or activity, follow the advice your own care team has given you.

Mental health and emotional wellbeing

It is understandable to feel anxious about blood transfusions after a reaction, especially if you need them regularly. Some people worry each time they sit down for a transfusion. Talking to your transfusion team about what happened, and what they will do differently next time, often helps a lot. If worry is affecting your sleep, mood or everyday life, tell your doctor — support is available, and you do not have to cope alone.

Prevention

It cannot always be prevented, but the risk can be lowered. Many blood services now filter white cells out of donated blood before it is stored, which reduces these reactions. If you have had a reaction before, your team can choose different types of blood products, take extra care with matching, and watch you more closely. Tell your care team about any past reaction every time you have a transfusion.

Screening programmes

There is no screening test for this reaction. Instead, your team relies on careful observation during transfusions and on your history of previous reactions.

Complications

If left untreated

• The fever and shivering can be very uncomfortable and tiring if the transfusion carries on
• A more serious reaction could be missed if symptoms are put down to this milder one
• Rarely, dehydration or feeling faint from a high temperature
• Feeling anxious about future transfusions, which can make treatment harder to cope with

Long-term outlook

The outlook is very good. A febrile non-hemolytic reaction is the mildest and most common type of transfusion reaction, and it usually settles within a few hours without any lasting effects. It does not damage your blood cells and does not mean you cannot have transfusions in the future. Your team will simply plan your next transfusion with a little more care.

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