The National Pathology Group has a guideline which it issues relating to the use of appropriate laboratory investigations. This may be freely accessed at :
www.npg.co.za/images/2013-12_NPG_Coding_Guidelines_V5191213.pdf
www.pathology.co.za/images/2013-12_NPG_Histology_Coding_GuidelinesV2.pdf
The website also contains recommendations for pathology testing for several conditions:
www.pathology.co.za/B_CommonSenPath.asp
Additionally the following international sites are of value: ARUP Laboratories: A national reference laboratory: www.aruplab.com Lab Tests Online : labtestsonline.org Royal College of Pathologists of Australasia: www.rcpa.edu.au/Home