Version 2.78

Term Description

Resin & T3 added to patient serum. Proportion of tracer bound by solid matrix measured. Result for patient serum divided by that of reference serum to give ratio. This test has been replaced by thyroid hormone binding ratio test.
Source: Regenstrief LOINC

Part Description

LP15921-7   Triiodothyronine resin uptake (T3RU)
Thyroid hormone uptake ("T-uptake") assays provide information on the number of thyroid hormone binding sites, consisting primarily of thyroid binding globulin, thyroxine binding prealbumin and albumin. Since both T4 and T3 bind to these proteins, different assay formats have used either labeled T3 or T4 (the classic T3 resin uptake uses T3). Various T-uptake assays can differ in the units reported (and even the phenomena being measured), requiring mindfulness when selecting LOINC codes. Being used in the calculation of free T3 and free T4 index (FTI), the T-uptake variants also proliferate into variants of FTI. The classic T-uptake reported as % represents the proportion of labeled thyroid hormone (either T3 or T4) added to a sample that remains unbound (modern assays: use LOINC 74793-1; T3 resin uptake method: 3050-2). T-uptake reported as ratio of patient /control is known as thyroid hormone binding ratio, or THBR or T-uptake ratio (use LOINC 74794-9). T-uptake % and THBR generally are inversely proportional to the number of unoccupied thyroid hormone binding sites present. Alternative assay methods that report T-uptake as "T-uptake units" are described as being directly proportional to the total binding capacity (use LOINC 74795-6).

However, the major rationale for measuring the T-Uptake was to obtain a factor for estimating the free T4 (the biologically relevant fraction). Now that Free T4 measures are widely available, accurate and more economical than measuring a T-uptake AND a TT4 , use of the uptake has been discouraged by most experts. Canada has taken the position of not paying for T-uptake measures. Source: Regenstrief LOINC

Reference Information

Type Source Reference
Mapping Guidance Regenstrief Help The only purpose of the T3RU is to calcluate the thyroxine free index [LOINC: 32215-6], which has fallen out of favor because the Free T4 provides the information that is really needed and is more accurate and less expensive than the T3RU. Mapper’s Guide for the Top 2000 plus LOINC Laboratory Observations

Fully-Specified Name

Component
Triiodothyronine resin uptake (T3RU)
Property
NFr
Time
Pt
System
Ser/Plas
Scale
Qn
Method

Additional Names

Long Common Name
Triiodothyronine resin uptake (T3RU) in Serum or Plasma
Short Name
T3RU NFr SerPl
Display Name
T3RU
Consumer Name Alpha Get Info
T3RU, Blood

Basic Attributes

Class
CHEM
Type
Laboratory
First Released
Version 1.0
Last Updated
Version 2.73
Order vs. Observation
Both
Common Test Rank Get Info
716

Language Variants Get Info

Tag Language Translation
el-GR Greek (Greece) Πρόσληψη της τριιωδοθυρονίνης από ρητίνη:Αριθμητικό κλάσμα:Χρονική στιγμή:Ορός/Πλάσμα:Ποσοτική:
Synonyms: Τ3
es-AR Spanish (Argentina) captación de resina de triyodotironina:fracción de un número:punto en el tiempo:suero/plasma:cuantitativo:
es-ES Spanish (Spain) Captación de triiodotironina por resina:Fracción numérica:Punto temporal:Suero o Plasma:Qn:
Synonyms: Cuantitativo
es-MX Spanish (Mexico) Captación de resina de triyodotironina (T3RU):Fracción numérica:Punto temporal:Suero o Plasma:Cuantitativo:
fr-CA French (Canada) T3 captation:Fraction numérique:Temps ponctuel:Sérum/Plasma:Quantitatif:
fr-FR French (France) Triiodothyronine absorption (T3RU):Fraction de nombres:Ponctuel:Sérum/Plasma:Numérique:
fr-BE French (Belgium) T3 captation:Fraction numérique:Temps ponctuel:Sérum/Plasma:Quantitatif:
Synonyms: T3 T3U
it-IT Italian (Italy) Triiodotironina resina, assorbimento:NFr:Pt:Siero/Plasma:Qn:
Synonyms: Assorbimento della triiodotironina resina Chimica Frazione numerica Plasma Punto nel tempo (episodio) Siero Siero o Plasma T3
ko-KR Korean (Korea, Republic Of) 레신 섭취 삼요드티로닌:숫자분획:검사시점:혈청/혈장:정량:
nl-NL Dutch (Netherlands) tri-iodothyronine harsopname (T3RU):getalsfractie:moment:serum of plasma:kwantitatief:
pl-PL Polish (Poland) Wychwyt trijodotyroniny:frakcja liczbowa:punkt w czasie:surowica lub osocze:ilościowy:
pt-BR Portuguese (Brazil) Triiodotironina.retenção:NFr:Pt:Sor/Plas:Qn:
Synonyms: ; T3RU; T3uptake; T3 binding ratio; RT3U; Triiodothyroinine uptake; T3U; T3 RU; T uptake; Triodothyrne; T-3; FT3; Fr; Number fraction; Percent; Point in time; Random; SerPl; SerPlas; SerP; Serum; SR; Plasma; Pl; Plsm; Quantitative; QNT; Quant; Quan; Chemistry
ru-RU Russian (Russian Federation) Трийодтиронин смолы захват (T3RU):КолДоля:ТчкВрм:Сыв/Плаз:Колич:
Synonyms: Количественный Количество отношение Плазма Сыворотка Сыворотка или Плазма Точка во времени;Момент
tr-TR Turkish (Turkey) Triiyodotironin reçine apteyk (T3RU):SayFr:Zmlı:Ser/Plaz:Kant:
zh-CN Chinese (China) 三碘甲状腺原氨酸树脂摄取:计数型分数:时间点:血清/血浆:定量型:
Synonyms: FT3;T3;T-3;T3.游离;T3.游离型;三碘甲状腺原氨酸.游离;三碘甲状腺原氨酸.游离型;三碘甲状腺氨酸;三碘甲状腺氨酸.游离;三碘甲状腺氨酸.游离型;三碘甲腺原氨酸;三碘甲腺原氨酸.游离;三碘甲腺原氨酸.游离型;游离 T3;游离三碘甲状腺原氨酸;游离三碘甲状腺氨酸;游离三碘甲腺原氨酸;游离型 T3;游离型三碘甲状腺原氨酸;游离型三碘甲状腺氨酸;游离型三碘甲腺原氨酸;甲磺安 RT3U;T 摄入;T 摄取;T3 RU;T3 摄取;T3 树脂摄入;T3 树脂摄取;T3 结合比;T3 结合比例;T3 结合比率;T3RU;T3U;三碘甲状腺原氨酸树脂摄入;三碘甲状腺原氨酸树脂摄取（Triiodothyronine resin uptake，RT3U） 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 摄取率;摄入;摄入率 数量型分数;数量或计数型分数;数量型分数或计数型分数 时刻;随机;随意;瞬间 血清或血浆

Example Units

Unit Source
% Example UCUM Units
% REGENSTRIEF
% eCHN

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

CodeSystem lookup
https://fhir.loinc.org/CodeSystem/$lookup?system=http://loinc.org&code=3050-2