Page 189 - Registrar Orientation Manual 2016
P. 189
Reference:
Effective date:
2015
Expiry date:
2018
Page:
15 of 28
Title: Laboratory Testing Guidelines (DRAFT)
Type:
Clinical Guideline
Version:
01
Authorising initials:
IgE ($41)
IgE specific testing costs over $300,000 a year. The test should be done selectively.
The Choosing Wisely recommendations include the following:
Don’t perform unproven diagnostic tests, such as immunoglobulin G (IgG) testing or an indiscriminate battery of immunoglobulin E (IgE) tests, in the evaluation of allergy.
Food specific IgE testing should not be performed without a clinical history suggestive of IgE mediated food allergy.
IgE testing in hospital is a SMO only test. To reduce inappropriate tests we limit testing to the most likely allergens. The requestor must specify the most likely allergen rather than just “food”.
IgG, IgA and IgM ($8 each)
Immunoglobulin levels cost $20,000 a year. These tests should be done selectively. The main indication is to quantify immunoglobulin levels in multiple myeloma and monoclonal gammopathy. Another indication is individuals with recurrent infections suspected of immune deficiency.
Procalcitonin ($26)
Testing costs more than $50,000 a year. We were using the procalcitonin in the work-up of patients with suspected meningococcal sepsis but no longer recommend it in undifferentiated sepsis. Procalcitonin should be used very selectively. Requests must be endorsed by a SMO.
Quantiferon Gold ($54)
Quantiferon Gold or Interferon Gamma Release Assay (IGRA) testing costs over $50,000 a year.
The test has a very limited role in the diagnosis of TB and should not be performed except in screening for latent TB infection in patients going on biologic therapy or screening TB contacts.
The DHB Shared Services Laboratory Test Referral Guidelines has the following on screening for latent TB (LTBI):
Contact screening for LTBI
Contacts aged 7 years and under: use a Mantoux test.
Contacts > 7 years: use a Mantoux test or IGRA or a Mantoux followed by IGRA (if Mantoux +ve)
Healthcare worker screening for LTBI
Use IGRA to screen health care workers for LTBI
Refugee screening for LTBI
Refugee children aged 7 years and under: use a Mantoux test
Refugee children aged 8- 15 years: Mantoux test or IGRA or a Mantoux followed by IGRA (if +ve) Refugees aged 16 and older: use either a Mantoux Test or IGRA
Screening for LTBI in immune-compromised people
Use IGRA
In some situations a clinician may elect to use both a Mantoux test and IGRA An IGRA is particularly recommended in the following:
BCG vaccinated people
Immune-compromised people
When it is considered a high risk the person will not return for the reading of their Mantoux
When it is impractical for the person to make repeat visits for sequential testing
