Laboratory Medicine
Test Directory / Thyroid Peroxidase Antibodies
Thyroid Peroxidase Antibodies
Brown clotted serum, gel barrier
| Test | Thyroid Peroxidase Antibodies |
|---|---|
| Common Abbreviations | TPO ,aTPO |
| Profile | NA |
| Tube type | Brown clotted serum, gel barrier |
| Clinical Indication | The measurement of autoantibodies against thyroid peroxidase is useful in identifying patients with autoimmune thyroid disease. Levels of anti-TPO antibodies are increased in greater than 90% of patients with active autoimmune thyroiditis. Anti-TPO antibodies activate complement and are thought to be significantly involved in thyroid dysfunction and the pathogenesis of hypothyroidism. In patients with autoimmune thyroid disease, anti-TPO antibodies are present in nearly all patients with Hashimotos thyroiditis and in greater than 70% of patients with Graves disease. Anti-TPO antibodies are also present in patients with atropic thyroiditis and primary myxedema. Low levels of anti-TPO antibodies can be detected in healthy individuals with normal thyroid function. The clinical significance of this has not been determined. The presence of anti-TPO antibodies is an indication for treatment in those patients with early/ compensated hypothyroidism. |
| Specimen Type | Blood |
| Sample type | Serum |
| Minimum Volume | 0.5mL If requesting more than 10 tests please send an additional brown clotted serum sample. |
| Special Precautions | No special requirements |
| Stability | 8 days at 20 - 25°C, 8 days at 2 - 8°C and 24 months at -20°C |
| Turnaround Time | Inpatient: 24 hours Outpatient/ GP: 24 hours |
| Laboratory | York |
| Reference Interval | < 34 IU/mL (Quoted by the manufacturer) |
| Limitations | Analysis should not be performed on haemolysed, icteric or lipaemic samples. The assay is unaffected by biotin < 40.9 nmol/L or < 10 ng/mL. No interference was observed from rheumatoid factors up to a concentration of 1350 IU/mL. 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 vitro tests were performed on 16 commonly used pharmaceuticals. No interference with the assay was found. In addition special drugs were tested. No interference with the assay was found. Refer to kit insert. In rare cases, high titres of antibodies to analyte specific antibodies, streptavidin or ruthenium can occur. |
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