General Information / Add On Requests
If additional tests are required on a sample already received in the laboratory, we require evidence that a responsible clinician has authorised the additional test(s). This can be via an additional paper request form or the electronic equivalent.
Routine Biochemistry blood samples are archived and kept for a minimum of three days. Beyond this, add-on test requests cannot be processed.
Please note that some analytes are labile and deteriorate rapidly and some tests are not suitable for requesting as ‘add-ons’. In these cases an add-on cannot be processed and a fresh sample will have to be taken. Most routine Biochemistry tests are stable for 3 days. Exceptions are:
Bicarbonate, Glucose, Ammonia, Lactate and HCG
Troponin T, D-Dimer, B12, Phosphate, Total Bilirubin, PSA
Folate, Ferritin, CK, Osmolality, Direct Bilirubin
Details of Blood Sciences initiated add-on testing can be viewed by Clicking here
Details of the Clinical Biochemistry Add-on policy can be viewed by Clicking here
Additional examinations may be requested up to 24hrs for coagulation samples and up to 3 days for haematology samples, however requests for blood films, malaria parasite screening and ESR testing are best performed on fresh samples that are <24hrs old. If you want to add further tests to a sample please ring (01904 72) 6802 option 1.
This procedure is designed to aid the additional analysis on haematology blood samples to ensure a full audit trail and conform with the principles of clinical governance. It is not for use with add-on test requests for urine and faecal analysis. All requests for additional tests must be accompanied by a signed request form clearly stating the tests required. This form is then used to generate further analysis. Haematology: D-Dimer and Paul Bunnell tests are only viable for 24 hours while Plasma Viscosity can be added after a maximum of 5 days.
Blood samples for serology are kept for 3 weeks, antenatal samples for 1 years. Needlestick samples are kept indefinitely. We also keep a small number of acute serum samples until a convalescent sample is received. If you want to add further tests to a blood sample we will require an additional request. Please phone 01904 726301 to make arrangements.
Most other samples are kept for at least 1 week before they are discarded. Some samples are kept longer depending on the tests requested. If you want to add further tests to a sample please ring 01904 725721 (York) or 01723 342288 (Scarborough). We will check if we still have the sample and then add the tests. Please note that in some cases the sample may be unsuitable and we will ask you to obtain a fresh sample.
Web Page updated 24: 07/05/20
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