Sample Acceptance Criteria

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Please note: Blood Transfusion has a more stringent labelling policy than Haematology due to increased risk to patients in case of labelling errors. For specific information about Haematology sample acceptance criteria, please refer to the Haematology sample acceptance criteria page.

Pathology-wide sample labelling criteria are detailed on the Specimen Labelling page. Information on completing request forms is available on the Pathology Requesting page.

The local Blood Transfusion Policy, which includes the information given below, is available via the link at the bottom.

Maximum Sample Volumes
EDTA anticoagulated sample bottles (Red lids) have a fill line printed on them and should not be overfilled, as this can lead to the formation of clots within the sample which may damage the analysers.

Minimum Sample Volumes
Note: All sample bottle plungers should be fully retracted to the bottom of the tube. Plungers that have not been fully retracted will be re-seated at the bottom of the tube before any evaluation of volume is performed.

Underfilled samples can hamper laboratory investigations in a number of ways. Analysers that have liquid level-sensing probes and are set to sample a specified distance under the surface may collide with the bottom of the bottle, potentially putting the analyser out of operation.

As the percentage volume of plasma in a blood sample varies between patients, absolute minimum sample volumes cannot be guaranteed because the plasma may be needed for further testing (e.g. antibody identification). As such, the volumes below are expected minimum volumes assuming that the patient needs no further investigation. Filling samples up to the fill line is preferable in all cases.

Please note if blood is required for a neonate, a maternal sample will be required that has been taken at either delivery or post-delivery. Please contact the laboratory for further information.

Minimum accepted volumes are as follows:

7.4ml EDTA bottle (Red): 2.0ml
3.4ml EDTA bottle (Red): 1.0ml
1.3ml paediatric EDTA bottle (Red): 0.3ml
4.7ml gel bottle (Brown): Please check with laboratory

Sample Suitability and Integrity
Specimens must be sent in the correct type of container(s) for the test(s) requested. A list of tests available in Transfusion and the corresponding container can be found in the Transfusion Test Information section. Alternatively, if a request is made using the Sunquest ICE computer system, the required type and number of specimen containers is printed on the request form.

All possible care must be taken not to contaminate request forms and exterior surfaces of collection tubes with blood or other substances that could present a health and safety risk to those handling them.

Leaking sample bottles will be rejected if they would pose a health and safety risk to those handling them.

Samples collected into bottles which have passed their expiry date will be rejected.

Sample Labelling
All specimens must be correctly labelled at the patient's side, using information from the hospital wristband where available. Where possible, confirm the patient’s identity by asking them to state their full name and date of birth. Sample tubes must never be taken away from the patient's side while they are unlabelled. Labelling of the specimen must be by hand. Printed labels will not be accepted by the transfusion laboratory.

Specimens must be labelled with a minimum of four unique patient identifiers. These should be:

  • Patient's forename (MUST be correctly spelt. Note that initials are not sufficient) - barring exceptions below
  • Patient's surname (MUST be correctly spelt. Note that initials are not sufficient) - barring exceptions below
  • Date of birth
  • Patient record number (District number)

Where a District number is unavailable, the patient’s NHS number is acceptable as long as it is recorded on both the form and sample. Where the patient has neither District nor NHS numbers, the patient’s home address can be used as an identifier as long as it is recorded on both the form and sample.

In an emergency, patients who cannot be identified must have a generated name and date of birth recorded on the sample as per hospital policy, but must still have a DIS number recorded as the identifier. MAJAX casualties from the Emergency Department will use the MAJAX number in place of the patient's name. These can then be merged with any previous records once the patient is identified.

Other information that must be included on the sample:

  • Signature of the person who took the blood
  • Date specimen was taken (and ideally time)

If the time is not recorded on the sample, it will be defaulted to a collection time of 00:01 on the date stated.

Failure to provide adequate sample identification will result in the specimen being discarded without analysis.

Any amendments to sample labeling must be performed whilst at the patient’s side. Once the sample has left the patient’s side, no subsequent amendments will be accepted. Amendments must only be to correct minor errors to otherwise correct patient demographics (e.g. information recorded in the wrong boxes, or an incorrect letter or number) but the original labelling must remain legible (e.g. struck through with a single line). If any amendments render the original labelling illegible, the sample will be discarded without analysis.

If the patient details on the specimen label do not precisely match those on the accompanying request form, the sample will be discarded without analysis and an appropriate report issued for the patient named on the request form. A Datix clinical incident record may be generated so that the requesting area investigates how the mislabelling has occurred.

Requesting blood products
As a minimum, the request form must be labelled with the following:

  • Patient's forename (MUST match that on most recent sample for crossmatches)
  • Patient's surname (MUST match that on most recent sample for crossmatches)
  • Date of birth  (MUST match that on most recent sample for crossmatches)
  • Patient record number (MUST match that on most recent sample for crossmatches)
  • Patient’s address
  • Patient’s gender
  • The requesting location
  • Name of the requesting doctor, their bleep number and their signature
  • Details of the component(s) required – to include the number, type and date required.
  • Details of any special requirements (e.g. CMV-negative, HEV-negative, irradiated)
  • Clinical information including reason for request
  • Date of request

Note that a request for blood products that includes a sample (e.g. Group & Save with Crossmatch) must fulfil the criteria for BOTH sample labelling and requesting blood products.

For more information specific to Crossmatch requesting and Group & Save requesting, please refer to the Group & Save and Crossmatch Guide.

Factors known to affect Transfusion test performance
Factors that may influence test results include phlebotomy, specimen transport and storage of samples.

Difficulty in taking blood from the patient or inadequate mixing may result in the sample clotting in the blood tube. This can produce fully clotted samples at one extreme, to microscopic fibrin clots at the other that can be difficult for the laboratory to detect. This can cause analyser damage, and/or clinical delay.

Transferring blood into the sample bottles from another syringe can cause haemolysis due to the shearing force experienced by the blood as it is forced out through the needle. This can prevent a valid blood group from being obtained and may require a repeat sample to be taken.

Diluting samples will dilute any antibodies present and may result in a clinically significant antibody being missed. Whenever a diluted sample is identified within the laboratory for a Group & Save, the sample will be rejected.

Specimen Transport and Storage
If the specimens are subjected to excessive heat when transported (e.g. left in the window of a car in direct sunlight) then the red and white cells within the sample will fragment. This may result in a haemolysed sample which then may be rejected.