Page 182 - Registrar Orientation Manual 2016

Reference:
Effective date:
2015
Expiry date:
2018
Page:
8 of 28
Title: Laboratory Testing Guidelines (DRAFT)
Type:
Clinical Guideline
Version:
01
Authorising initials:
BNP ($44)
NT-Pro BNP testing costs nearly $400,000 a year. Many tests add little to patient management. The DHB Shared Services Laboratory Test Referral Guidelines note:
The natriuretic peptides are extremely useful for evaluation patients with non-specific symptoms of early chronic heart failure. In particular, the strong negative predictive value of a normal result is very useful and enables evaluation and treatment to be directed elsewhere.
A clearly high result supports heart failure, although in most acute cases this is clinically obvious through other means and measurement adds little to management or prognosis.
The value is much less well established for guiding ongoing anti-failure treatment, and at present they have a secondary role only. NICE guidelines (UK) recommend their use for this purpose be restricted to difficult patients under specialist management. Current NHF/NZGG guidelines do not specifically restrict their use in this setting but have not encouraged it.
We recommend:
The BNP should be used in patients with suspected but undiagnosed heart failure. Do not do a BNP if the result will not change management.
Do not use the BNP routinely to monitor therapy in heart failure.
The laboratory will not process repeated BNP requests within 48 hours.
Calcium, Magnesium and Phosphate ($2.5)
We recommend these should be requested selectively (for example in malignancy or CKD): Do not do Calcium, Magnesium and Phosphate unless clinically indicated.
Cholesterol and Lipids ($5.5)
The Choosing Wisely recommendations include the following:
Do not routinely test for hyperlipidaemia in those with a limited life expectancy. We also recommend:
Do not do ‘screening’ lipids during an acute hospital admission.
Do not request lipid studies within a short period after of previous testing.
Creatinine, Urea and Electrolytes ($2.5)
Routine testing is not indicated in all admissions. Many tests are repeated unneccessarily. As noted under the general recommendations from Choosing Wisely:
Don’t do regular tests but test in response to clinical questions.
Don’t do repeat tests if clinically stable; repeat only when clinically indicated.
Do not repeat laboratory tests for patients transferred into the ED who have laboratory results within reference ranges available from outside hospital.
Don’t do screening tests in low risk patients undergoing low risk surgery.
We also recommend:
Do not repeat the creatinine and electrolytes if they were normal unless there are clinical indications to suggest a likely change (eg hypotension, reduced urine output).