TSH with Reflex to Free T4 TSHR
| Method(s) | Chemiluminescent Immunoassy | ||||||||||
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| Specimen Required | |||||||||||
| Collect | One 5 mL gold (SST) top tube. Also acceptable: Lithium heparin plasma, EDTA plasma. |
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| Transport | 1 mL serum at 2-8°C (Min: 0.5 mL) |
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| Stability | Ambient: 8 hours (FT4); Refrigerated: 2 days; Frozen: 14 days (TSH) |
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| Schedule | Daily | ||||||||||
| Billing Code | 1010605 | ||||||||||
| CPTCode | 84443 | ||||||||||
| Notes | If TSH is abnormal, a Free T4 is reflexively ordered. See also Thyroid Cascade. |
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| Preferred Specimen Collection Device(s) | |||||||||||
| Reference Interval | |||||||||||
* Reference range is applicable for infants 30 days and older. Neonatal reference range has not been established for this method.
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