Pathlab utilise bpac guidelines to reflex FT4 and/or FT3 based on TSH results. This process is fully automatic, and the reflex tests are reported with the TSH result. Pathlab is seeing many requests for FT4 where the TSH is within reference limits. Some of these requests may be valid and they do not want to restrict useful tests. However, FT4 is often requested with TSH for no good reason.
Pathlab will shortly be removing FT4 from the front page of the electronic order form. It will remain searchable and requestable to requestors. Their intention is to encourage best practice as detailed in the bpac guidelines contained in the link attached. Pathlab will also take the opportunity to make minor adjustments to other tests on the e-order form, namely moving IgE, Iron studies and Cortisol to other pages and making NT-ProBNP a searchable test only. Be assured all of these tests are still available to request.
Pathlab and Waikato Hospital will be changing the report name of Iron Saturation to the more accurate Transferrin Saturation on reports in the very near future. The results will not change, only the name of the test. Results will still be expressed as %.
Diagnosis of thyroid dysfunction
The relationship between TSH and FT4 makes TSH a very sensitive marker of thyroid function; if FT4 is decreased by 50%, TSH will increase about 100 times. In most patients TSH is the preferred initial test when checking for thyroid disease. If TSH falls outside the reference interval, additional testing will be automatically triggered:
When to request both FT4 and TSH
Monitoring of thyroid hormone supplementation in men and non-pregnant woman
For other thyroid conditions or settings consult the bpac guidelines or an endocrinologist.
Please send any feedback to John Woodford, Service Lead Biochemistry.
This week the Pinnacle Incorporated Executive Committee has written to Dr Ashley Bloomfield, Director-General of Health and Labour MPs across the Midland region asking them to reconsider lowering the screening age for Māori and Pacific people.
Read moreAPEX union members will take staggered strike action between Saturday 22 and Friday 28 March, 2025.
Affecting lab testing across Te Manawa Taki, APEX union members from Awanui will walk off the job from 25 to 27 March, while Pathlab workers will go on strike from 24 to 26 March and Medlab/TLab workers from 22 to 28 March.
For the latest updates on lab services in your area, please check the website(s) of the pathology labs you use.
The B4 School Check (B4SC) is a universal, comprehensive check for all four-year-old’s that includes height and weight, vision and hearing, immunisations, oral health, and behavioral and developmental components.
View detailsNational Cervical Screening Programme screening updates.