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Add on tests

Add On Tests General Criteria and Information 

All add on tests must be on samples taken from the patient in the previous 72 hours

Procedure for requesting Add-On Tests Electronically

  1. Using i-Care, medical staff should select the patient for whom they wish to add-on a test.

  2. Expand the ‘Services’ folder on the left hand side of the screen and click on the link:

  3. View/create Pathology add on test

  4. If any add on tests have already been requested they will be listed here.

  5. Click the add new test link in the top right hand corner.

  6. Complete the form: date of sample, time of sample and test(s) are mandatory fields.

  7. Once the form  is complete click the Submit button.

1. Requesting add on tests manually

This procedure must be followed when i-Care is unavailable (and for GHH requests) : Users are instructed via the Laboratory Medicine website ( to complete the normal Combined Pathology request form in the usual way. The comment ‘Add-on request’ is added to the form and sent to the laboratory through the usual system.  The form must be signed by a clinician – tests will not be added without a signature.  In these instances the clinician will be informed, preferably by telephone. If this is not possible, then a Problem set (PRBLM) is added and a report issued with the comment ‘Add on test request not signed  by clinician’. 
If a test is required urgently, the requesting clinician should telephone the appropriate laboratory to alert staff as well as carrying out the requesting procedure .  Laboratory staff should add a notepad message recording the name of the clinician making the verbal request.
Requests for additional tests  from General Practice and other external users can be made by telephone.

Biochemistry Tests

Criteria  Action/ Analyte
 Samples normally received on ice (Lactate, Ammonia)  No add on possible
 Samples normally separated immediately (Renin, P3NP)  No add on possible
 Tests which can only be added to a sample received within 4 hours of collection  Glucose (serum)
 Tests which cannot be added on once sample has been spun and analysed (5hr limit)  hs-Troponin I
Tests which can only be added on to samples protected from light D Bilirubin
Analyte unstable once samples stored at 2–8 °C Bicarbonate
 Tests which MUST NOT be added 24 hours post collection  


PTH (if stored at room temperature)

 Tests which MUST NOT be added more than 48 hours after collection  PTH (If stored at 4-8̊C)
 Samples up to 72 hours post collection  Any tests not specified above
 Samples greater than 72 hours old  Add-on tests not available

Immunology Tests

Tests which cannot be added ;
Tryptase, CH50, FCIN.  Cryoglobulin – needs special collection conditions. CD4 counts (LYMPH) must be added within 48hrs.

Haematology tests

Tests may be added on to the appropriate sample type if there is sufficient volume available.  Generally Coagulation tests (INR, APTT and Fibrinogentest) can be added on only within 8 hours to a Citrate sample.  Retics may be added to an EDTA sample within 12 hours and ESR within 48 hours of sample draw time.  For all other tests, please consult the laboratory.

Microbiology requests

Microbiology requests cannot be dealt with via the Pathology ‘add-on’ facility.  Microbiology require a separate, signed request for their tests.  We can however provide sample for completion of these tests where a suitable specimen is available.  Please contact Microbiology for details.


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