Medical Oncologist
CION Cancer Clinics
How much blood is arranged before cancer surgery, and why | CION Cancer Clinics
The number of units of blood arranged depends mainly on the operation. For many cancer operations the blood bank only checks your group and keeps a sample, with no bags set aside. For operations that tend to bleed more, a few matched units are reserved in your name, and unused units go back into stock. This page explains how that number is chosen and why the family may be asked for donors. CION Cancer Clinics’ surgical oncologists in Hyderabad can talk this through with you.
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Medically reviewed by Dr. Muralidhar MuddusettyConsultant Surgical Oncologist · MBBS (AIIMS), MS (Surgery, AIIMS), DNB (Surgical Oncology), MRCS (Edinburgh) · last reviewed September 2026, next review due September 2027
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On this page
- How many units of blood are arranged for cancer surgery?
- What happens between the blood request and the operation?
- What makes the team arrange more blood?
- What is the difference between group and save and crossmatch?
- What do families worry about when they hear the number?
- What should you ask about the blood arranged for your operation?
- What should you have ready for the blood bank?
- Common questions about blood arranged for surgery
The short answer
How many units of blood are arranged for cancer surgery?
There is no single number. Each hospital keeps a list, often called a blood ordering schedule, that sets how much blood to arrange for each type of operation. For many operations it is none: your blood group is checked and a sample is held. For operations that tend to bleed more, a few matched units are reserved in your name.
Why a list, rather than a guess
The list is built from how much blood the same operation has actually used over time. It stops blood being reserved and wasted for operations that rarely need it. It also makes sure enough is ready for the operations that often do.
Why your number may differ from the list
The surgeon or anaesthetist can ask for more than the list suggests. A low haemoglobin, a blood thinner, a large tumour, a second operation in the same area or a rare blood group can each change the request. They can also ask for plasma or platelets if your clotting tests are not normal.
The number reserved says nothing about how serious your cancer is. It is not a prediction of how much blood you will receive.Behind the scenes
What happens between the blood request and the operation?
The request
After the pre-operative check, the team sends a form to the blood bank naming the operation, the date and how much blood to prepare.
Your sample is tested
The blood bank finds your group and screens for antibodies, proteins that could react against donated blood. If any are found, matching takes longer, so the date may need a little room.
Units are matched
For operations on the reserve list, donated units are tested against your sample and labelled with your name. They are held for a short period around the operation.
Unused units go back
If no blood is needed, the units are released back to general stock for someone else. Ask the billing desk whether anything is charged for units reserved but not used.
On the morning of surgery
The ward confirms with the blood bank that your sample is still current and the units are ready. If your date has moved, a fresh sample may be taken before you go to theatre.
Not sure whether this applies to you?
Ask an oncologistThe reasons
What makes the team arrange more blood?
Four things push the number up. The family does not decide any of them.
The type of operation
Operations on the liver, the pancreas, large blood vessels or the bones of the pelvis generally need more blood arranged than a breast or skin operation.
Often need more
- Large tumours in the abdomen or pelvis
- A repeat operation in the same area
- Operations after radiotherapy to that area
A low haemoglobin before surgery
If you start with less, a smaller loss matters more. Chemotherapy, poor eating and slow bleeding from the tumour are common reasons for it. Teams often try to raise a low haemoglobin before the day when there is time.
Blood thinners and clotting problems
Medicines such as aspirin, clopidogrel or warfarin, and liver problems that affect clotting, can mean plasma or platelets are arranged too. Never stop a blood thinner yourself. Your doctors decide the timing.
Antibodies or a rare group
If matching blood is hard, the blood bank may prepare units well ahead so the search does not happen on the day.
Side by side
What is the difference between group and save and crossmatch?
Group and save
Crossmatch
Your group is found and your sample is kept
Donated units are tested against your sample
No units are set aside in your name
A set number of units are labelled and reserved for you
Used when the operation rarely needs blood
Used when the operation more often needs blood
Blood can still be matched fairly quickly if bleeding starts
Blood is ready to go straight to theatre
Families are less often asked for donors
Families are often asked to replace the reserved units
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Commonly believed
What do families worry about when they hear the number?
"Four units arranged means four units will be given."
The number arranged is a safety margin, not a plan. Many people who have units reserved receive none. Blood is given one unit at a time, with a check before each.
"If we bring more donors, the operation will be safer."
Donors replace stock. They do not change how the operation goes. Bringing far more people than the blood bank asks for only means more people wait, are screened and go home. Send the number asked for, with a spare name or two in case someone does not pass the checks.
"Only a group and save means the team is cutting corners."
A group and save alone is what guidelines suggest for operations that rarely bleed heavily. The blood bank can still prepare matched blood during the operation if it is needed. Reserving blood that is almost never used would take it away from patients who need it that day.
"Reserved blood is wasted if it is not used."
Units that are not used go back into stock before they expire and are given to other patients. Reserving blood, when there is a reason to, is not a waste.
Being straight with you
What should you ask about the blood arranged for your operation?
This page cannot tell you how much blood your own operation needs. That depends on the operation, your reports and your hospital's schedule. What you can do is ask clear questions before the day, and write the answers down so the whole family hears the same thing.
Four questions for the ward or the blood bank
Has blood been grouped only, or matched and reserved? How many units, and why that number? Does the blood bank need replacement donors, and by which date? Is there a charge for units that are reserved but not used?
When the usual plan does not suit
A standard blood order does not suit everyone. If you will not accept donated blood, have reacted to a transfusion before, have been told you carry antibodies, or have a rare blood group, tell the surgical team at the first visit. They can involve the blood bank early, or discuss ways to reduce blood loss during the operation.
Whether and how to operate is decided by your treating team. These questions help you follow the plan, not change it.Before you go
What should you have ready for the blood bank?
- The blood request form signed by the doctor
- The patient's name, age and hospital number exactly as on the file
- Any old blood group card or transfusion record
- Names and phone numbers of family who can donate
- A note of any past reaction to blood
- Your scheme or insurance card, for the billing desk
Questions we are asked
Common questions about blood arranged for surgery
Why is blood being checked if my surgery is small?
Even for smaller operations your blood group is usually checked and a sample is kept. That is a group and save, not a reservation. It lets the blood bank prepare blood quickly in the unusual event of heavy bleeding.
How long is reserved blood kept for me?
Units are usually held around the date of your operation and a short time after. If surgery is postponed, the blood bank may release them and ask for a fresh sample. Tell the ward if your date changes.
Do we have to replace every unit arranged?
Blood banks set their own rules. Some ask for donors to replace units reserved, others only for units used. Ask the blood bank directly so the family knows exactly how many donors are needed and by when.
Can the number of units change on the day?
Yes. If your haemoglobin has dropped or the plan has changed, the team may ask for more. If bleeding during surgery is heavier than expected, the blood bank can prepare more while the operation continues.
Will blood arranged for me go to someone else?
Once it is released after your operation, yes. Blood reserved in your name is held for you only while it is needed. Stock is shared, and the donors your family brings help keep it available for everyone.
Are plasma and platelets arranged the same way?
Sometimes. If your clotting tests are abnormal or your platelet count is low, the team may arrange plasma or platelets alongside red cells. Platelets keep only for a few days, so they are arranged close to the operation.
What if the blood bank does not have my group?
The hospital's blood bank can usually source matched blood from other licensed blood banks. For rare groups this takes longer, which is why telling the team early matters. Never buy blood from anyone outside a licensed blood bank.
Is the charge for blood covered by schemes?
Blood bank charges for units used are often included under Aarogyasri, CGHS, ECHS, EHS and most cashless insurance when the operation is approved. Rules for reserved but unused units vary. Ask the billing desk before surgery.
Meet the Specialists
17+ senior cancer specialists. One panel for your case.
Trained at AIIMS, Tata Memorial, and leading international centres. Combined 150+ years of experience. Every complex case is reviewed by 3+ of them — together.
Medical Oncologist
Dr. C. Raghavendra Reddy
MBBS(Gold Medal), DNB(General Medicine), DM(Medical Oncology)(Gold Medal)
Medical Oncologist
Dr. Bharati Devi Gorantla
MBBS, MD(General Medicine), DM(Medical Oncology)(Adyar,Chennai), ECMO, MRCP SCE(UK)
Medical Oncologist
Dr. Owais Mohammed
MBBS, MD (General Medicine), DrNB (Medical Oncology), ECMO, MRCP SCE (Medical Oncology) (UK)
Medical Oncologist
Medical Oncologist
Surgical Oncologist
Dr. Muralidhar Muddusetty
MBBS (AIIMS), MS (Surgery) (AIIMS), DNB (Surgical Oncology), MRCS (Edinburgh)
Surgical Oncologist
Surgical Oncologist
Surgical Oncologist
Dr. Vinay Mamidala
MBBS, MS(General Surgery), M.Ch(Surgical Oncology), FMAS, FARIS(Ongoing)
Surgical Oncologist
Radiation Oncologist
Radiation Oncologist
Radiation Oncologist
Hematologist
Surgical Oncologist
Dr. Vajja Sandeep Kumar
MBBS, MS (General Surgery), DrNB (Surgical Oncology), FALS Oncology
Surgical Oncologist
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Sources
- NICE — Blood transfusion (NG24)
- NHS — Blood transfusion
- American Cancer Society — Blood transfusion and donation
This page is general information, not a prescription. Do not change or stop any treatment based on what you read here. If anything is worrying you, contact your own treating team — or call our helpline and we will help you reach the right specialist.
Keep reading
Related pages
Blood Transfusion Around Cancer SurgeryWhen reserved blood is actually given, and what to watch forReplacement Donors: Finding Them and the RulesHow to find the donors the blood bank asks forBuilding Haemoglobin Before SurgeryStarting with more reserve can lower what is neededThe Days Before Your OperationEverything else to sort out before admissionCost, Insurance and Schemes for Cancer SurgeryWhat the package covers, blood charges included
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