The time limits for adding on the most common tests are shown below, any other tests should be referred to the Duty Clinical Scientist (Ext 43235).

 

Time limits for adding tests (after collection)
Tests	Maximium Time after collection
UE (with Potassium)	2 Hours
UE (without Potassium)	12 Hours
Plasma Glucose (Grey Top Tube)	72 Hours
Serum Glucose (Yellow / Red Top Tube)	2 Hours
Serum PTH (Yellow / Red Top Tube)	4 Hours
Plasma PTH (Purple Top Tube)	12 Hours
Phosphate	12 Hours
Biocarbonate	12 Hours
AST/Iron	12 Hours
Lipid Profile (+ or - HDL)	72 Hours
LFT	72 Hours
All other tests	72 Hours
LDH	Cannot be added onto an old request. LDH becomes unstable when the sample has been stored at 4 Celsius. Please send a repeat sample.

Heartlands/Solihull Hospital - Additional tests may also be performed on previously received specimens if sufficient is available in storage. For Hospital users of the service please use the electronic add on system. External users of the service should contact the relevant department to discuss if an add on test is possible.

Good Hope Hospital -  All requests for add on tests on inpatients must be on the appropriate pink form. If this form is not available then the normal request form can be used and must state clearly that it is an add on test. If the form is not signed then the test will not be added on and the Clinician will be informed. If the test is required urgently, the requesting Clinician should phone the appropriate lab that performs the test. Requests for additional tests from GP’s and other external users can be made by telephone.