Requesting Additional Tests (add-on requests)

In some circumstances it is possible to add tests onto samples that are already in the laboratory. This will depend on sample stability, tube type and for some tests there will be timing restrictions.

In general, routine biochemistry tests can be added on upto 6 hours after the sample has been received in the laboratory, except for paediatric specimens where there is a time limit of 2 hours.

In general, routine haematology tests can be added on upto 24 hours after receipt in the laboratory.

How do I add on tests to a sample that has previously been sent to the lab?

A request form should be completed in full, as you would when sending samples to the laboratory.  This is detailed in the request form completion page.  Add on requests over the telephone will not be accepted.

In addition, as much information as possible should be provided indicating which sample to add the tests to. 

Examples - "please add CK test to sample collected at 13:40"

                      "please add magnesium test to sample number 4621596.X". 

                      "please add TFT tests to sample collected in A/E on 6/8/10"

Providing these sorts of comments will minimise the risk of tests being added to the wrong sample, which can result in unneccesary delays to patient management. 

When is it inappropriate to add a particular test?

There are a range of circumstances in which it is not appropriate to add certain tests to a sample already in the laboratory.  Please consult the tests and tubes database for test-specific information, or contact the laboratoy for advice.


Page updated: 16/08/11 Updated by: Micheal O'Sullivan

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