Collecting peripheral blood stem cells

This information covers each stage of the stem cell or bone marrow collection process. The clinical apheresis unit forms part of the haematology and transplant day unit (HTDU) and is run by specially trained nurses who will co-ordinate and carry out your stem cell collection.

If you have any further questions, please speak to the specialist nurses involved in the collection process (apheresis/transplant co-ordinators).

What is a stem cell?

A stem cell is an immature parent cell which can grow and divide into red blood cells, white blood cells and platelets. The type of blood cell that a stem cell will develop into depends on the specific needs of the body at any one time.

Stem cells originate in the bone marrow, but it is possible to move them into the peripheral blood stream and collect them from there.

What is bone marrow?

Bone marrow is a spongy tissue found inside certain bones in the body mainly the sternum (breastbone), pelvis, humerus (upper arm), femur (thigh) and ribs, and it is where stem cells originally grow.

Why are my stem cells or bone marrow needed?

Bone marrow or peripheral blood stem transplants are used in the treatment of illnesses such as leukaemia, lymphoma, myeloma or aplastic anaemia. The aim of a transplant (high-dose therapy) is to help get rid of any remaining disease with high doses of chemotherapy and occasionally radiotherapy.

Most cancer drugs and some radiotherapy treatments damage normal tissue as well as cancer cells. The cells most affected are those lining the gut, the skin, hair follicles and the bone marrow stem cells. These can recover completely, given time.

Bone marrow stem cells are particularly vulnerable to intensive chemotherapy and radiotherapy. Healthy bone marrow stem cells can be collected before high dose chemotherapy/radiotherapy and then returned to you after the completion of intensive treatment to help ‘rescue’ your body from the damaging side effects of chemotherapy. These cells can travel into the bone marrow spaces and grow into healthy functioning cells.

How are stem cells collected?

  • from the bloodstream (peripheral blood stem cell collection/harvest by apheresis)
  • from the bone marrow (bone marrow harvest)

How are stem cells encouraged into the blood stream?

The collection of stem cells from the peripheral blood is the most used method of cell collection.

At any one point, there are only a limited number of stem cells in the peripheral blood. To collect them from your blood, we need to increase the number available and move them out of your bone marrow where they originate into your bloodstream where they can be collected or harvested.

We generally do this using a combination of chemotherapy and growth factors (GCSF). Occasionally we may just use growth factors alone, but this is rare. This process is called mobilisation. In general, we can collect stem cells from you on our first attempt. However, some patients may need to undergo a second mobilisation attempt if an insufficient number of cells are collected the first time around.

Some patients may also need to have a drug called Plerixafor in combination with GCSF to help them mobilise stem cells adequately. Plerixafor enhances the effect of GCSF and increases the number of stem cells in the bloodstream by helping to release them from the bone marrow. It is given as a small injection under the skin by nursing staff on the haematology day unit the evening before your planned harvest procedure.

Virology testing

Before bone marrow or stem cell collection, your blood will need to be tested for certain blood-bound viruses. These include Hepatitis B, Hepatitis C, Human Immunodeficiency Virus (HIV), HTLV 1 and 2 (Human T-cells Lymphotropic Virus), Syphilis and Cytomegalovirus (CMV).

These tests are a legislative requirement when storing and processing any human tissue and are governed by The Human Tissue Authority. This test will need to be done within 30 days of the collection.

Samples for research and cell storage

Occasionally, stored cells are not used for treatment. They may be used in research or be discarded. Before your cells are collected, we will ask you to sign a consent form. Please feel free to ask your consultant or a member of the team any questions about this.

Medical assessment

Before we move forward in collecting stem cells or bone marrow from you, you will be seen in clinic by a haematology consultant and specialist nurse. They will go through the procedure in detail with you as well as make a full assessment of your medical condition and disease status to ensure this is the best treatment for you.

What does the chemotherapy do?

Chemotherapy ‘encourages’ stem cells to come out of your bone marrow and into your peripheral blood stream. Many different types of chemotherapy regimens can be used for this purpose. Most commonly, we use cyclophosphamide, or we can use the course of chemotherapy you are currently having as part of your normal treatment, such as R-CHOP, DHAP, GDCVP, ICE, VIDE or ESHAP.

What is GCSF?

GCSF (Granulocyte Colony Stimulating Factor) occurs in the body naturally and controls bone marrow reproduction. When given in combination with chemotherapy or in high doses, it encourages stem cells to move from the bone marrow into the peripheral blood stream where they can be collected.

GCSF is given daily as 1 or 2 small injections under the skin before a stem cell harvest. We can teach you or a relative to give these injections. Alternatively, we can arrange for a district nurse to give them to you.

Do not stop having these injections. The injections of GCSF may cause some bone pain and flu-like symptoms. Taking a simple painkiller such as paracetamol or co-codamol may help.


We will ask you to sign a consent form agreeing to accept the treatment that you are being offered. The basis of the agreement is that you have had The Christie’s written description of the proposed treatment and that you have been given an opportunity to discuss any concerns.

You are entitled to request a second opinion from another doctor who specialises in treating this cancer. You can ask your own consultant or your GP to refer you. Your consent may be withdrawn at any time before or during this treatment.

Should you decide to withdraw your consent, a member of your treating team will discuss the possible consequences with you.

When will the cells be collected?

The specialist nurses in the apheresis unit of the HTDU will arrange for you to have regularly monitoring of your full blood count (FBC). They will advise you of the most likely day that your blood counts will recover to allow a stem cell harvest to occur.

On that day, they will take a special blood test called a predictive count to monitor the number of stem cells which have moved out into your bloodstream. When these tests indicate that there are enough stem cells in your peripheral blood stream, you will have your stem cells collected.

These blood tests will generally be taken a set number of days after your chemotherapy has been completed and when you have had a set number of injections.

You will need to attend the haematology and transplant day unit (department 26) at 8am on the morning of these blood tests, as the predictive test takes a few hours to perform. These tests may need to be done for several days before your stem cell levels are adequate for collection to take place.

The first day of testing is generally a Monday but please ensure you are free to attend for several consecutive days on the week designated for your harvest. Everyone is different and individual, so the exact day your blood counts are adequate to allow collection may be different for each person.

You should arrange for someone to drive you to and from the hospital on the days you are having your stem cells harvested. Occasionally an overnight stay may be required, and we would advise that you bring an overnight bag with you.

How are stem cells collected (harvested)?

  • Stem cells are collected using a machine called a cell separator (apheresis machine).
  • Blood flows out of a needle inserted into the crook of your arm into the machine via plastic tubing connected to the machine. This blood is then spun through a centrifuge at high speed. At intervals during the procedure, stem cells are removed and collected into an attached bag. The remaining blood is returned to you through a cannula in your hand.
  • If you have poor veins, you may need a temporary plastic needle (femoral line) inserting into the groin at the top of the leg. However, we will make a full assessment of your veins before the procedure and discuss any problems with you if necessary.
  • If you already have a Hickman line in place this can be used to return the blood to you. Unfortunately, we are not able to use PICC lines to carry out the procedures as these do not provide the machine with an adequate blood flow through it.
  • You can eat and drink normally before and during the procedure. Once you are attached to the machine however, you cannot be disconnected until the procedure is completed. This takes about 4 to 6 hours.
  • Your blood pressure and pulse will be monitored at the beginning and end of the procedure. If you feel dizzy or light-headed during the procedure it is important to let the nurse know.
  • The machine is removing and returning blood to you continuously and even though there will be a very small amount of blood in the machine at any one time, it may be enough to make you light-headed.
  • The machine uses an anticoagulant to prevent the blood from clotting. This may cause tingling around the lips, cheeks or fingertips as it can cause the calcium levels in your blood to drop. Let the nurse know if this happens. Oral tablets or an infusion into the cannula will prevent any complications.
  • The collection is usually completed in 1 or 2 days. You may go home after the first day and we will advise you if you need to return the next day. If so, you will need more G-CSF injections that evening. Occasionally an overnight stay may be required, and we would advise that you bring an overnight bag with you.
  • You may feel tired after the procedure, and we advise you to drink plenty of fluids and rest.
  • There will be a nurse in attendance throughout the procedure.

What is a bone marrow collection (harvest)?

You are only likely to require this procedure if there are medical indications which would prevent you from having a stem cell harvest or in rare cases where your doctor feels this may be the best means to supplement a peripheral stem cell collection.

  • This type of collection is carried out under a general anaesthetic and in theatres. You will be admitted into hospital the day before the harvest, and you will need to have some blood tests and have an examination by a doctor. The doctor will discuss the procedure with you again and ask you to sign a consent form agreeing to the procedure.
  • You are not allowed to eat or drink anything from midnight the night before the harvest. On the day, we will ask you to shower and put on a hospital gown. Remove all your jewellery (except a wedding ring). When the theatre staff are ready for you, a porter and nurse will take you to theatre.
  • The anaesthetist will insert a cannula (a plastic needle) into the back of your hand so you can have medication to put you to sleep.
  • 2 doctors or nurses will collect the bone marrow from the back of your hip bones. They will put a needle into the bone and remove the bone marrow with a syringe and transfer this to a blood bag. The collection takes about an hour to complete and will remove about 1 to 1.5 litres of bone marrow. Your body can replace this in less than 3 weeks.
  • A dressing is put over the puncture sites there will be at least 2 of these, one on each hip to stop the site from bleeding and the staff will take you to the recovery room to ‘wake up’.
  • When you wake up, you may have some fluids running into the cannula in your hand. This is to replace some of the fluid that has been taken during theatre. When you are properly awake, we will take you back to the ward. You may also need a blood transfusion at this point, but this is rare.
  • The staff on the ward will monitor you regularly and check the puncture sites, your blood pressure, temperature and pulse. They will also monitor your oxygen levels. You will then be able to drink and have some painkillers for the soreness in your back, hips and throat.
  • Normally, you will be discharged home the next day. We advise you to rest for the next few days and return to work the following week. We will give you some painkillers.
  • You will require at least 7 to 10 days to recover, and occasionally you will have lower back pain for a little longer.

Side effects of each procedure

G-CSF/Stem cell harvest

  • Injection site reactions
  • Bone pain
  • Flu-like syndrome
  • Venous thrombo-embolism (rare)
  • Splenic rupture (very rare)
  • Poor mobilisation – may require repeat harvest (5 to 10%) or bone marrow harvest (uncommon)
  • Insertion of temporary central venous catheter (femoral line) if peripheral venous access is inadequate
  • Exceptionally rare but serious – capillary leak syndrome, symptoms include generalised swelling, puffiness, less frequent urination, difficulty breathing, abdominal swelling and extreme tiredness
  • There are also theoretical concerns regarding the risk of developing leukaemia, although the available evidence indicates that donors treated with G-CSF are not at increased risk
  • Exceptionally rare risk of death

Bone marrow harvest

  • General anaesthetic
  • Back pain
  • Anaemia – may require blood transfusion or iron supplementation
  • Infection at harvest site
  • Inadequate harvest that may require peripheral blood stem cell harvest

What happens to the cells after they have been collected?

With both types of collection procedures, the stem cells are taken to the laboratory and counted to calculate exactly how many have been collected. We also test to ensure there are no infections in the stem cells. Stem cells can safely survive for many years when frozen so they are stored in liquid nitrogen until needed.

Your consultant may decide to discard any stored cells:

  • if not enough cells have been collected,
  • if the cells are no longer needed, or
  • if the cells are infected.

With your consent, any cells not used for your treatment may be used for research rather than discarded.

What happens next?

When we have collected sufficient stem cells, we will arrange an outpatient appointment for you to see your consultant. He or she will discuss your next treatment option. If you are going straight to transplant, we will give you a date for admission at this meeting. This is a good time for you to bring a list of questions with you.

Cyclophosphamide chemotherapy – what is involved?

Cyclophosphamide is the most common chemotherapy regime which we use to help us collect stem cells. This is often arranged after you have completed your standard treatment and is given primarily in combination with growth factors to allow us to move the stem cells from your bone marrow to your blood stream so that they can be easily collected.

Day 1 (usually Monday or Tuesday)

This chemotherapy is given as an outpatient, through a central line or cannula over 2 hours.

  • Before the treatment starts, we will give you some intravenous anti-sickness drugs through your central line or through a peripheral cannula.
  • The chemotherapy is a colourless liquid and can irritate your bladder and in worse cases cause cystitis. To prevent this, we will give you drug called mesna through your cannula before your chemotherapy. After your chemotherapy, we will give you a tablet form of mesna to take.

Day 2

  • GCSF: The day after this chemotherapy, you will need to start having daily injections of growth factor (GCSF). These are small injections given just under the surface of the skin. We can teach you or a family member to give yourself injections or we will arrange for a district nurse to give them to you. Do not stop the injections.
  • They may cause a throbbing bone pain (as your bone marrow is being stimulated to produce stem cells) and/or make you have flu-like symptoms. Taking simple painkillers such as paracetamol is helpful.

What complications should you look out for?

  • We advise you to drink 2 to 3 litres of fluid for the next few days to help flush your kidneys and bladder. Once at home, if you experience any pain or problems when passing water or any blood in your urine, please contact The Christie Hotline.
  • You may experience some nausea and even sickness. We will give you anti-sickness tablets to take home with you.
  • You may also have diarrhoea.
  • The chemotherapy will suppress your blood counts for a short time and make you more vulnerable to infections. We will give you some extra antibiotics to take. Keep a check on your temperature while you are at home.

Contact The Christie Hotline immediately on 0161 446 3658 if you have any problems or are feeling unwell.

Last updated: September 2023