TPO antibody

Alternative names, keywords

Thyroid peroxidase antibodies, anti-TPO, anti-thyroid peroxidase, antithyroid antibodies.

Samples required

Clotted blood (gold cap, 5 mL tube).  Smaller tubes are available for paediatric samples.

Test indications

Routine thyroid autoantibody test to help predict clinical hypothyroidism, usually in patients with increased TSH.

TPO antibodies at high titre are found in patients with Hashimoto's thyroiditis (95%), primary myxoedema (90%) and Graves disease (18%). Low titre TPO antibodies may occur in goitre, thyroid carcinoma and in other organ-specific autoimmune diseases. Antibodies may be predictive of future thyroid disease so clinical and biochemical follow up is advised.

Factors affecting test performance/ results

Samples should not be taken from patients receiving therapy with high biotin doses (i.e. > 5 mg/day) until at least 8 hours following the last biotin administration.

In in vitro studies, itraconazole caused increased anti‑TPO concentration findings at the daily therapeutic dosage level.

In rare cases, interference due to extremely high titres of antibodies to analyte-specific antibodies, streptavidin or ruthenium can occur.

Results should always be assessed in conjunction with the patient’s medical history, clinical examination and other findings.

Reference range

<34 U/mL
_{Source: Roche Cobas^® TPO kit insert 03-2015, V4.0}

Turnaround time

1 week

Enquiries

Biochemistry (Automation)