What does this LOINC code represent?

This LOINC code identifies a lab observation, measurement, question, or clinical concept in a standardized format.

Is this enough to understand my test result?

No. The code identifies the test or observation, but the interpretation depends on the actual result, reference range, and clinical context.

LOINCActiveBoth

LOINC Code 74795-6: Total thyroxine binding capacity [Relative ratio]

Name: LOINC Code 74795-6: Total thyroxine binding capacity [Relative ratio]
Creator: HealthAssure Clinical Team
Published: 2026-05-21T08:59:55.155Z

74795-6 is a LOINC code used to identify Total thyroxine binding capacity [Relative ratio] in laboratory and clinical observation data. You may see this code in lab systems, lab reports, EHR exports, interoperability feeds, or other structured clinical data exchanges. LOINC codes identify tests, measurements, observations, survey items, and clinical questions in a standardized way. It is associated with the component Total thyroxine binding capacity. It is commonly used with the system or sample type Ser/Plas.

Reviewed by HealthAssure Clinical TeamUpdated 21 May 2026

What is this code?

LOINC codes identify tests, measurements, observations, survey items, and clinical questions in a standardized way. It is associated with the component Total thyroxine binding capacity. It is commonly used with the system or sample type Ser/Plas.

When is it used?

Used in lab systems, EHRs, and clinical data exchange.
May identify a test, observation, survey item, or clinical document request rather than a diagnosis.
Status: ACTIVE
Order vs observation: Both

What it does not mean

The code identifies the observation or test, not the actual result.

Key facts

Total thyroxine binding capacity in Serum or Plasma

Total thyroxine binding capacity

T-uptake in T uptake units. T uptake units bear a rough INVERSE relationship to the other T uptake (See AxSym package inserthttp://www.promtest.am/tests/thyroid-diagn/T-Uptake.pdf), but actually measures a different phenomenon (total binding capacity instead of unbound hormone).

Bind; Chemistry; Endocrine; Endocrinology; Levothyroxine; Levo-thyroxine; L-thyroxine; Pl; Plasma; Plsm; Point in time; QNT; Quan; Quant; Quantitative; Random; Relative ratio; SerP; SerPl; SerPlas; Serum; Serum or plasma; SR; T4; T-4; thyroid hormone; Thyrox; Thyroxin; Thyrx; Tot; Total T4; Total TBC; Totl; TT4; T-uptake

Where you may see this code

You may see this code in lab systems, lab reports, EHR exports, interoperability feeds, or other structured clinical data exchanges.

Common synonyms

Total thyroxine binding capacity [Relative ratio]Total thyroxine binding capacity in Serum or PlasmaTotal TBC SerPlTotal thyroxine binding capacityCHEMTotal thyroxine binding capacity, BloodRelRto

Frequently asked questions

Code details

Code74795-6

SystemLOINC

Display nameTotal thyroxine binding capacity [Relative ratio]

DescriptionTotal thyroxine binding capacity

Short nameTotal TBC SerPl

ComponentTotal thyroxine binding capacity

PropertyRelRto

TimingPt

System (specimen)Ser/Plas

ScaleQn

ClassCHEM

Example unitsT-uptake units

StatusACTIVE

Order/ObservationBoth

Flags

BillableNo

Valid clinical useNo

Source

SourceLOINC

Version2.82

Releasemain

First released2.48

Last changed2.82

Consumer names

Total thyroxine binding capacity, Blood

Part names

Total thyroxine binding capacityRelRtoPtSer/PlasQnRelative RatioPoint in time (spot)Serum or Plasma

About this content

This page is prepared by HealthAssure's clinical team using official coding standards from LOINC. AI tools assist with drafting explanations, which are then reviewed and verified by healthcare professionals for accuracy. This content is for informational purposes and does not replace professional medical advice. Meet our team.