Version 2.77

Part Description

LP28551-7   Thyroxine free index
Free thyroxine index (FT4I, FTI) is calculated from total hormone (TT4) and any one of the thyroid hormone uptakes - see LOINCs 3050-2 (Triiodothyronine resin uptake, T3RU), 74794-9 (Thyroid hormone binding ratio, THBR), 74793-1 (Classic T-uptake), and 74795-6 (Total thyroxine binding capacity). It adjusts total hormone levels for the number of binding sites to provide a better picture of thyroid status than total hormone levels. Results may vary depending on which T-uptake is used. If that level of distinction is important, users should look to the associated T-uptake code. However, little reason exists to depend on a Free T4 index today now that Free T4 measures are widely available, accurate and more economical than measuring a T-uptake and a TT4. Source: Regenstrief LOINC

Fully-Specified Name

Component
Thyroxine free index
Property
MCnc
Time
Pt
System
Ser/Plas
Scale
Qn
Method
Calculated

Additional Names

Short Name
FT4I SerPl Calc-mCnc
Display Name
Free T4 index Calc [Mass/Vol]
Consumer Name Alpha Get Info
Free T4 Index, Blood

Basic Attributes

Class
CHEM
Type
Laboratory
First Released
Version 2.07
Last Updated
Version 2.73
Change Reason
FTI is fundamentally MCNC but many labs report as unit-less.
Order vs. Observation
Both
Common Test Rank Get Info
669

Formula (Readable)

FTI=(T4 concentration) x (% TU)/100 -- a pure fraction

Language Variants Get Info

Tag Language Translation
es-AR Spanish (Argentina) índice de tiroxina libre:concentración arbitraria:punto en el tiempo:suero/plasma:cuantitativo:
es-ES Spanish (Spain) Índice de tiroxina libre:Concentración de masa:Punto temporal:Suero o Plasma:Qn:Calculado
Synonyms: Cuantitativo
es-MX Spanish (Mexico) Índice libre de tiroxina:Concentración de masa:Punto temporal:Suero o Plasma:Cuantitativo:Calculado
fr-CA French (Canada) Indice de thyroxine libre:Concentration de masse:Temps ponctuel:Sérum/Plasma:Quantitatif:Calculé
fr-FR French (France) Thyroxine libre Index:Masse/Volume:Ponctuel:Sérum/Plasma:Numérique:Résultat calculé
fr-BE French (Belgium) Indice de thyroxine libre:Concentration de masse:Temps ponctuel:Sérum/Plasma:Quantitatif:Calculé
Synonyms: IT4L T4 T4L,fT4
it-IT Italian (Italy) Tiroxina libera, indice:MCnc:Pt:Siero/Plasma:Qn:Calcolato
Synonyms: Chimica Concentrazione di Massa Indice di tiroxina libera Plasma Punto nel tempo (episodio) Siero Siero o Plasma Tiroxina libera
ko-KR Korean (Korea, Republic Of) 티록신 유리 지수:임의농도:검사시점:혈청/혈장:정량:
nl-NL Dutch (Netherlands) thyroxine vrij index:massa/volume:moment:serum of plasma:kwantitatief:berekend
pl-PL Polish (Poland) Wolna tyroksyna, indeks:stężenie masowe:punkt w czasie:surowica lub osocze:ilościowy:obliczony
pt-BR Portuguese (Brazil) Indice de Tiroxina.Livre:ACnc:Pt:Sor/Plas:Qn:
Synonyms: ; FTI; FT4I; T7; T4 Free; T-4; FreeT4; Thyrox; Thyrx; Thyroxin; Levothyroxine; Levo-thyroxine; L-thyroxine; Arbitrary concentration; Point in time; Random; SerPl; SerPlas; SerP; Serum; SR; Plasma; Pl; Plsm; Quantitative; QNT; Quant; Quan; FT4; FR; Non-protein bound; Chemistry
ru-RU Russian (Russian Federation) Тироксин свободный индекс:МассКонц:ТчкВрм:Сыв/Плаз:Колич:Вычисленный
Synonyms: Количественный Массовая концентрация Плазма Сыворотка Сыворотка или Плазма Точка во времени;Момент
tr-TR Turkish (Turkey) Tiroksin serb indeksi:KütlKons:Zmlı:Ser/Plaz:Kant:Hesaplanmış
zh-CN Chinese (China) 游离型甲状腺素指数:质量浓度:时间点:血清/血浆:定量型:计算法
Synonyms: FT4 FT4;FT-4;T4.游离;T4.游离型;游离 T4;游离型 T4;游离型甲状腺素;游离甲状腺素;甲状腺素.游离 FT4I;FTI;T7;游离型甲状腺素指数（Free Thyroxine Index，FTI）;甲状腺素游离指数 T4;T-4;四碘甲状腺原氨酸;四碘甲腺原氨酸;左旋四碘甲状腺原氨酸;左旋四碘甲腺原氨酸;左旋甲状腺氨酸;左旋甲状腺素;左旋甲状腺素（Levothyroxine，Levo-thyroxine，L-thyroxine）;甲状腺氨酸 化学;化学检验项目;化学检验项目类;化学类;化学试验;非刺激耐受型化学检验项目;非刺激耐受型化学检验项目类;非刺激耐受型化学试验;非刺激耐受型化学试验类 可用数量表示的;定量性;数值型;数量型;连续数值型标尺 时刻;随机;随意;瞬间 水平;浓度;质量浓度(单位体积) 游离 游离T4 游离四碘甲状腺原氨酸 游离型四碘甲状腺原氨酸 游离甲状腺素 血清或血浆 计算;计算型方法 非蛋白结合型 非蛋白质结合型

Example Units

Unit Source
{Index_val} Example UCUM Units

LOINC Terminology Service (API) using HL7® FHIR® Get Info

CodeSystem lookup
https://fhir.loinc.org/CodeSystem/$lookup?system=http://loinc.org&code=32215-6