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Blood Sciences General Information

Opening times

We are open for the receipt of specimens and the analysis of the majority of routine tests:
• From 09:00 to 18:30 Monday to Friday
• From 09.00 to 13.00 Saturday
Out of hours:
• Between 18:30 and 09:00 Monday to Friday
• 13:00 Saturday to 09:00 Monday
• Bank Holidays
During out of hour times, the laboratory is staffed by a single biomedical scientist to provide a service for emergency and essential hospital test requests.

Urgent Requests

The majority of routine tests have a turnaround time of 2 to 3 hours from the time of sample receipt. Providing a sample is received before 16.00, a result is normally available the same day.

We provide an urgent analysis service for a limited repertoire of tests if essential for the immediate management of a critical patient. We aim to have results available within 60 minutes of receipt of specimen.

Procedure for RD&E Hospital in-patient emergency requesting

During normal working hours (inc. Saturday morning and Bank Holidays):

Outside normal working hours:

NB. A telephone call is essential – failure to telephone the laboratory with details of the urgent request will result in samples being treated as category 3 samples, and will be accorded priority on the next scheduled batch and abnormal results telephoned as soon as they are authorised.
Forms marked with “please phone” are treated as category 3 samples. They are accorded priority on the next scheduled batch and results telephoned as soon as they are authorised.

Samples from ITU, ED AMU & NNU are automatically assigned category 1 status & treated as urgent.

Procedure for GP emergency requesting:


External referrals

Referral From External Organisations

We welcome external referrals from any organisation, for any of our test repertoire. If you are a new requestor please complete the following form: New Requestor Form v3

We will process any sample referred to us meeting our sample labelling criteria.

Please Note: In line with the requirements of ISO15189:2012, each sample request will be considered a Service Level Agreement.  To arrange a formal Service Level Agreement please contact the laboratory manager. Our Quality Statement for referred work can be found here : Quality statement May 2019 (374 downloads)

We undertake to inform referring centres, without undue delay, in the event of circumstances that may adversely affect the reliability of results or turnaround times.

Examination by referral laboratories

The laboratory requires the assistance of outside referral laboratories to perform analyses that the laboratory does not perform routinely, this may be for examinations or for consultant opinions. Deciding which laboratory to use is be based on numerous factors (e.g. expertise and skill, competency, references, cost, turnaround time, proficiency, proximity, accreditation status, EQA participation).

The Blood Sciences Laboratory is responsible for selecting the referral laboratories and takes steps to monitor the quality of performance and ensure that the referral laboratories are competent to perform the requested examinations. This is achieved by letter which is sent to all referral laboratories. A register of all the approved referral centres is kept for all the departments within the Blood Sciences Quality Management System, and this information is requested and updated annually.

Requesting Categories

Sample requests are triaged into 3 categories.

Category 1 – ‘STAT’ or ‘1 hour urgent’

These samples take priority over all other samples. These specimens are treated as genuinely urgent, and will be processed immediately on arrival.   However, in order to process urgent samples, the requesting Doctor must follow the procedures as outlined in ‘Urgent requests above’.

Samples from specific wards: ITU, A&E, EMU, CDU, STAU, WYAC, MTU,PAU & NNU are automatically assigned category 1 status & treated as urgent.

Urgent request results are not usually telephoned, but are available on ward terminals within one hour. If results are abnormal, they fall within our telephone policy and are telephoned as soon as they are validated.

Category 2 – Waiting patient or ward staff.

Suitable only for short turnaround time tests.

A sample from a waiting patient or ward staff should be brought to the Blood Sciences laboratory and identified as a sample from staff or patient intent on waiting for the result. The sample is processed through the urgent system and undergoes immediate labelling, booking-in and centrifugation, then is taken to the appropriate section for analysis. An analyser print out is given to the person waiting.

Category 3 – ‘Three hour urgent’

Samples that are received with the urgent box marked, but no prior urgent telephone request had been made.

These samples are allocated to the routine reception area, but are given priority over other routine samples. The results are not telephoned unless they are abnormal and fall within our telephone policy. Results should be available on ward terminals within three hours.

Add on tests

If add-on tests are required, please note the following information:

Requests made from within the hospital:

Requests from Primary Care:

Order of Draw

Telephoned Results

Results falling outside of the limits below will be telephoned to the requestor or requesting location wherever possible. For GP requests every endeavour will be made to contact the surgery within working hours. Devon Doctors will be contacted out of working hours.

Parameter                             Lower limit                                       Upper limit

Acute Kidney Injury flags

All stage 3 flags

All stage 2 flags to GP’s and RDE OPD patients

All AKI 1/2/3 in children to requesting clinician or paediatric registrar

Ammonia                                                                                           30 mmol/L
Ethanol                                                                                             400 mg/L
AST                                                                                                F 465 M 555 iu/L
ALT                                                                                               F 495 M 615 iu/L
Amylase                                                                                             300 u/L
Bicarbonate                                                                                      <10 mmol/L
Bile                                                                                                       >9 umol/L
CSF glucose                             2.0 mmol/L                                      6.0 mmol/L
Calcium (corrected)             1.60 mmol/L                                      3.00 mmol/L
Carbamazepine                                                                                 20 mg/L
Creatine kinase                                                                                  5000 iu/L
Cortisol                                                                                               100 nmol/L

Adult Creatinine (Not renal patients)                                        354 mmol/L

Children < 16 years                                                                        200 mmol/L

CRP (GP only)                                                                                 300 mg/L
Digoxin                                                                                              2.3 µg/L
Ethanol                                                                                              400 mg/L
Gases                                                                                                All results

Adult Glucose                           2.5 mmol/L                                25.0 mmol/L

Children <16 years                  2.5 mmol/L                                15.0 mmol/L

Lactate                                                                                               2.4 mol/L
Lithium                                                                                              1.4 mmol/L
Magnesium                             0.50 mmol/L                                  1.50 mmol/L
Neonatal bilirubin                                                                            300 mmol/L
Paracetamol                       Any concentration above 10 mg/L
Phenytoin                                                                                             25 mg/L
Phosphate                                 0.50 mmol/L                                 4.00 mmol/L

Potassium (hospital)                   2.8 mmol/L                               6.4 mmol/L

Potassium (primary care)          2.8 mmol/L                                6.0 mmol/L

Salicylate                                                                                          300 mg/L

Adult Sodium                              120 mmol/L                             150 mmol/L

Children <16 years                    130 mmol/L                              150 mmol/L

Theophylline                                                                                      23 mg/L
Troponin T (GP only)                                                                       14 ng/L
Urate  (Pregnant women only)                                                   >  340 mmol/L

Adult Urea (Not renal patients)                                                      30.0 mmol/L

Children <16 years                                                                             10 mmol/L


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