Page 183 - Registrar Orientation Manual 2016

Reference:
Effective date:
2015
Expiry date:
2018
Page:
9 of 28
Title: Laboratory Testing Guidelines (DRAFT)
Type:
Clinical Guideline
Version:
01
Authorising initials:
CRP ($8)
CRP testing costs about $600,000 a year and many tests add little to patient management.
We recommend:
Do not request CRP unless it is clinically indicated.
Do not repeat the CRP without a good reason.
The CRP is not a de facto measurement of “unwellness”.
If clear indications exist, a CRP can be used to detect occult inflammation.
A CRP does not help in the ongoing management of an obvious infection such as cellulitis and the clinical progress of a patient is a much better guide to management of most patients.
There is never justification for daily CRPs!
Ferrritin and Iron (Ferritin is $7, Iron and TIBC $4)
Iron studies rarely provide additional information to a ferritin in iron deficency.
We recommend:
Do a ferritin in the initial investigation of patients with suspected iron deficiency. Do iron saturation in the investigation of suspected haemachromatosis.
FSH ($10)
The Choosing Wisely recommendations include the following:
Do not perform FSH levels in women in their 40s with irregular/abnormal bleeding.
HBA1C ($12)
HBA1C testing costs over $200,000 a year. More tests are being done as HBA1C is used for
diagnosis as well as monitoring but many tests are repeated too frequently. We recommend:
Do not repeat the HBA1C within 3 months of previous testing in Type 2 Diabetes.
Repeat testing (within 3 months) may be helpful in selected patients with very poorly controlled Type 1 diabetes and in pregnancy but the laboratory will not repeat the HBA1C within 28 days.
Homocysteine ($44)
The DHB Shared Services Laboratory Test Referral Guidelines note:
Plasma homocysteine may be elevated in vitamin B12 or folate deficiency, or genetic defects of B12 or folate metabolic pathways. Raised homocysteine levels are associated with increased risk of cardiovascular disease and stroke. However, homocysteine lowering interventions (e.g. folate and vitamin B6 supplementation) do not modify cardiovascular risk, despite lowering homocysteine levels. This suggests that homocysteine does not have a causative role in vascular disease so rroutine homocysteine testing is not recommended as part of CV risk assessment.
We have now restricted homocysteine testing to SMO requests only.
LFTs ($2.5)
We recommend:
Do not request routine LFTs in all admissions. Do LFTs only if clinically indicated.
Do not repeat LFTs without a good clinical reason.
Do not repeat LFTs too frequently (and virtually never within 24 hours).
With very mildly abnormal LFTs in sick patients a full screen of tests for all possible causes of liver disease is not indicated. It is often best to ask the GP to repeat the LFTs after an interval. If chronic viral hepatitis is a possibility consider requesting HBsAg and Anti-HCV antibody.