Additional Requests
Requesting additional blood science tests (Biochemistry, Haematology and Immunology)
We are aware that on occasion it is necessary to request additional tests for a sample already in the laboratory. We will accommodate additional requests where possible but in order to limit the interruption to workflow within the laboratory the routine practice should be to add tests to future samples or that the patient is re-bled.
Situations that may require additional testing include:
- Acute investigations where the result will change immediate management
- eg. Amylase, paracetamol & salicylate, Troponin T, HCG - Time critical and difficult to collect samples
- B12/folate/Ferritin prior to transfusion or discharge
- Samples from outpatients
- Paediatric and neonatal samples
- Drug screens
- Additional immunology tests
- Additional coagulation tests (please ring laboratory ext 4728 within 6 hours of venepuncture)
Situations not mentioned above are usually inappropriate for additional requesting.
If the request fulfils these criteria the additional test will be accepted provided that:
- The laboratory has the correct specimen type with sufficient sample remaining
- The test does not require special sample handling
- The request is within the sample stability timeframe indicated below
(for tests with less than 4 days stability):
| Unstable Add-on NOT appropriate |
Within 24 hours of venepuncture | Within 48 hours of venepuncture | Up to three days after venepuncture |
| Ammonia | CSF lactate | Haematology tests | U&E, LFT |
| Bicarbonate | Digoxin | Vitamin B12 | Bone, Mg |
| Lactate | Folate | TFT’s | |
| Glucose (if non fluoride tube) | Paracetamol | BNP | |
| Lipids | |||
| Cortisol |
Requesting additional tests
To request an additional test on a previously sent inpatient sample, please use the:
Haematology samples are routinely retained for a maximum of 2 days.
Biochemistry samples are routinely retained for a maximum of 4 days.
Immunology samples are routinely retained for a maximum of 14 days
The laboratory processes add on requests, received via Millennium, with the same priority as routine ward requests.
If an additional test is required urgently, please provide a fresh sample.
For clinically critical requests where this is not possible please contact the relevant department.
- Haematology: ext 4728
- Immunology: ext 4737 (ANCA and GBM only)
- Biochemistry: ext 4240 or bleep via switchboard out of hours
Requesting additional tests on an already sent GP sample
To request additional tests on a previously sent GP sample, please use the