Hospitals & Science

The NTMRL is one of the three sections of the NTML;

Reference Laboratory, Bacteriology, Surveillance/Epidemiology. The National Transfusion Microbiology Reference Laboratory (NTMRL) is a unique, single site, specialised laboratory, whose primary role is to undertake all of the microbiological confirmatory/reference testing for the National Blood Service. Samples ‘reactive’ in the microbiology screening assays performed in the Processing Testing and Issue (PTI) testing laboratories - samples from blood, tissue and stem cell donations, and ante-natal screens - are referred to NTMRL to determine the true status of the donors/patients involved. This service is critical to the NBS:

• as part of its overall responsibility for the health of the blood donors who provide the basic raw materials for the NBS, ensuring any need for clinical intervention is identified
• in the clinical context of the ante-natal screening performed
• an invaluable means of managing the supply of blood donors, ensuring that the large number of ‘screen reactive’ donors who are confirmed as not truly infected are returned to the active donor panel as soon as possible
• to provide a comprehensive screening service, outside of PTI, for the more extensive range of markers required for tissue and stem cell products
• to provide an effective and appropriate means of testing those samples found to be unsuitable for testing on the PTI automated testing systems

In addition to this core activity, NTMRL undertakes testing for the additional infectious disease markers, non-mandatory for blood donors, donor qualification screening for reinstatement to active status; specific screening for product release when this cannot be undertaken within the PTI screening laboratories.

NTMRL also undertakes the formal Lot Release Testing of all infectious disease marker screening kits used by the NBS.

Finally, the NTMRL is the main source of additional microbiological expertise, advice and guidance within the NBS to the NBS operational testing laboratories, and may be called upon to work urgently with a testing laboratory to solve a range of specific scientific microbiological problems.

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Tel: 0208 2582733 / 2816

Fax: 0208 2582846

Email NTMRL@nbs.nhs.uk

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• The laboratory is not primarily concerned with reproducing the results obtained by the NBS screening laboratories, but in determining whether the donor is indeed infected, or may potentially be suitable for reinstatement to the active donor panel, either directly or via an alternative screening assay
• The referral of samples to the NTMRL is the responsibility of the referrer. Samples must be shipped in accordance with extant NBS and HSE regulations. It is up to the referrer to ensure that, if required, mechanisms are in place to confirm delivery of samples to the NTMRL, although, like any Reference Laboratory, NTMRL does not have the resource or the ability to actively confirm the receipt of all samples referred
• The provenance of referred samples is out of the control of the NTMRL, and thus its quality systems are based upon the assumption that each sample referred has been identified correctly by the referrer, and that the correct investigation(s) has(have) been requested
• For all donation/donor investigations the original pilot tubes (both serum and plasma) should be referred. The sample type of choice for virus serology is serum or plasma, and for NAT is plasma. However because the residual serum in the serum pilot tube is usually at too low a level for reliable automated sampling, NTMRL investigations are generally performed using the plasma tube, and the serum is archived
• It is the responsibility of the referrer to ensure that the samples referred are of the quality required for confirmatory testing. Samples that are haemolysed, lipaemic or otherwise in poor or unsuitable condition are rejected by the NTMRL and reported as ‘Unsuitable for testing’

All NBS samples referred must be accompanied by a correctly completed NTMRL request form. Non-NBS sites should use the NTMRL referral forms if at all possible, although other forms may be accepted following discussion and prior agreement with NTMRL. The NTMRL referral forms do contain boxes to include patient name and hospital number for use with any clinical samples and where the referrer considers this information necessary. NBS samples will normally only be booked in using the donation number and donor ID as primary identifiers.

• All samples referred for confirmatory testing are booked into the NTMRL sample database and allocated an NTMRL accession number. All samples referred are individually booked-in even if the sample is an additional volume for a sample already referred, e.g. archive or an additional sample tube. A full audit trail of every sample received is maintained
• It is assumed that all NBS laboratories referring donor samples follow extant red book instructions, in particular performing initial and repeat testing on the same, preferably clotted, sample
• The majority of samples referred are from donations found to be repeat reactive on screening at some stage, and the algorithms developed reflect this. Nonetheless the algorithms are broadly appropriate for any clinical diagnostic or other investigations performed. Additional or different investigations may be performed if required by the referring laboratory and if considered valid by NTMRL, or if dictated by circumstances
• All results and reports issued are authorised by the scientific staff of the laboratory, although reports on samples confirmed negative at the primary investigation stage are automatically generated and not individually signed
• The NTMRL reports the results of the investigations performed, centrally, to Surveillance, NTML. If the report needs to be sent to a different location, that should be clearly indicated on the referral form.
• Requests for any repeat samples required from donors are made via the referring laboratory/site unless other arrangements have been agreed.