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Chapter 6

BLOOD REQUEST AND SAMPLE COLLECTION

PRACTICE POINTS

  • All requests need to have full patient identification, date, reason for transfusion, number of units of each component required and signature of prescribing physician.
  • All blood samples for pre-transfusion testing must be accompanied by a request form specifying patient details, test required, blood component required, reason for transfusion and location of patient.
  • Autologous blood has limited use when donor blood is available.
  • Directed donations should be discouraged. Voluntary donation is safer, cost effective and more practical.

6.1 REQUEST FOR BLOOD PRODUCTS – IN THE HOSPITAL

The request for blood products should be in writing at the hospital blood bank or transfusion laboratory using a special request form. The following data should be on this form:

  • Patient identification (full name, age or birth date and hospital identification number).
  • Diagnosis and indication for transfusion.
  • Requested product(s) and number of units.
  • Date and time of request and desired delivery.
  • Name, signature and phone/pager number of the prescribing physician.

If known the following information must be mentioned:

  • ABO blood group and RhD.
  • Did the patient receive transfusion earlier? If YES when was the last?
  • Has the patient been pregnant?
  • Are previous transfusion reactions known?
  • Have red cell antibodies ever been detected?

6.2 REQUEST OF BLOOD PRODUCTS – AT THE BLOOD ESTABLISHMENT

The hospital blood bank or transfusion laboratory orders all needed blood products from the regional or national blood establishment.

6.2.1 Ordering and delivery of blood products

Any order from hospital blood bank or transfusion laboratory to the regional or national blood establishment by phone must always be confirmed by a special form that is faxed to the blood establishment. Electronic ordering is also possible. Consultation about the blood transfusion policy should always be possible with the Clinical Consulting Service calling directly or indirectly via the issuing department.

Ordering is based on the decision to transfuse and comprises several steps:

  • Completion of the request form.
  • Collection and labelling of the samples with patient identification.
  • Documentation in the patient file.
  • Transportation to the laboratory.

The hospital blood bank should be supplied with a stock of regular blood components, sufficient to cover a week’s consumption including emergencies.

Stock control is a responsibility of the hospital blood bank.

The blood establishment delivers the products and confirms the agreement (written) with the hospital blood bank or transfusion laboratory. 

6.2.2 Emergency requests

In unforeseen (emergency) cases blood products may be delivered outside the regular hours. The ordering procedure does not deviate from the normal procedure except that there is usually contact with the Clinical Consulting Services. Therefore the blood establishment is contactable 24 hours per day.

In case the public telephone is not working, and if applicable, the national emergency telephone network to which all hospitals and blood establishments are connected may be used.

6.2.3 Directed blood products

Directed donations are not recommended as irradiation of blood products is not currently available in Cambodia.

Directed donations increase the risk of transfusion associated Graft versus Host Disease (GVHD). The recipient’s immune system is unable to recognise the transfused homozygous HLA lymphocytes as foreign, whereas the transfused lymphocytes recognise the host cells as foreign and mount an immunological attack.

Transfusion associated Graft Versus Host Disease leads to profound marrow aplasia with a mortality rate > 90%. Survival is rare with death typically occurring within 1–3 weeks of first symptoms.

NB: In Cambodia relatives are recruited to donate instantaneously on some occasions. This type of blood donation is not in compliance with WHO and IRC recommendations and increases the risk of transfusion transmissible infection and transfusion-associated Graft versus Host Disease.

6.2.4 Autologous blood donation

Autologous blood donated preoperatively increases the risk of receiving any transfusion. Preoperative autologous blood should only be used in exceptional circumstances, such as a patient with a rare blood group or multiple red cell antibodies whose transfusion requirements cannot be met with allogeneic blood.

Preoperative autologous blood collection is only recommended where there is a reasonable expectation that blood will be required for the condition or procedure. Checking the local Maximum Blood Order Schedule (MBOS) for estimated blood usage requirements during surgery will assist in decision making.

The indications for transfusion of autologous blood should be the same as for allogeneic blood.

Patient suitability for autologous collections is based on the ability to tolerate several venesections taken over a short period of time, age, adequate venous access, and reliable dates for elective surgery.

Autologous blood collections are subject to the same testing criteria as allogeneic collections within the Blood Service. Autologous blood should be tested for hepatitis B, hepatitis C, HIV 1/2 and syphilis

Should a test on a collection fail initial screening, the patient and referring doctor will be notified and further collections suspended pending the results of further testing. Collections confirmed as positive for a transfusion-transmissible infection are discarded and no further collections undertaken.

In order to protect the safety of the allogeneic system, autologous blood which is not transfused to the patient cannot be used for any other patient.

Autologous blood collection is subject to the same collection, storage and processing requirements as allogeneic blood collection. 

6.3 TAKING BLOOD SAMPLES FOR COMPATIBILITY TESTING

Taking blood samples for compatibility testing is one of the critical elements of the clinical transfusion chain. One of the most frequent errors is ‘wrong blood in tube’, where erroneously two patients have been mixed up during the sample collection procedure – a human error with sometimes dramatic consequences.

6.3.1 The sample collection procedure

  1. Only collect samples from one patient at a time.

  2. Complete collection and labelling before performing any other task.

  3. If the patient is conscious at the time of taking the sample, ask him or her to identify themselves by given name, family name, age/ date of birth and any other appropriate information.

  4. Ask the patient to spell his/her given and family name if able.

  5. Check the patient’s name against:
    - patient’s identity wristband or label,
    - patient’s medical notes, and
    - completed blood request form.

  6. If the patient is unconscious, ask a relative or a second member of staff to verify the patient’s identity.

  7. Take the blood sample into the type of sample tube required by the blood bank. For adults, this is usually 4 mL, with no anticoagulant. Sample volume and anticoagulant may vary according to local protocols. Paediatric samples are often 1 mL or less.

  8. Label the sample tube clearly and accurately with the following information at the patient’s bedside at the time the blood sample is being taken:
    - patient’s given name and family name, - patient’s age and or date of birth,
    - patient’s hospital reference number,
    - patient’s ward,
    - date, and
    - identification of person taking the sample.

    Ensure that the patient’s name is spelt correctly. Do not label the sample tube before obtaining the specimen because of the risk of putting the patient’s blood into the wrong tube.

  9. If the patient needs further red cell transfusion, send a new blood sample for compatibility testing.

This is particularly important if the patient has had a recent red cell transfusion that was completed more than 24 hours earlier. Antibodies to red cells may appear very rapidly as a result of the immunological stimulus given by the transfused donor red cells.

A fresh blood sample is essential to ensure that the patient does not receive blood which is now incompatible.

When a patient has been transfused in the preceding 3 months, a sample can only be held for 72 hours while awaiting a decision to transfuse. Otherwise the sample can be held for up to 7 days (according to local protocols).

It is vital that all the details on the blood sample tube label match those on the blood request form and are uniquely identifiable with the patient.

Any failure to follow correct procedures can lead to incompatible transfusions.

Blood bank laboratory staff are acting correctly if they refuse to accept a request for compatibility testing when either the blood request form or the patient’s blood sample are inadequately identified or the details do not match. If there is any discrepancy, they should request a new sample and request form.

6.4 TRANSPORT OF BLOOD SAMPLES

Blood samples for compatibility testing should be transported closed (capped) and in a rack, placed in a proper (clean and disinfected) container.

Do not transport samples in syringes with or without attached needles.

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