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.

LOINCActive

LOINC Code 35521-4: Clinical trial protocol Direct access to source data+documents section

Name: LOINC Code 35521-4: Clinical trial protocol Direct access to source data+documents section
Creator: HealthAssure Clinical Team
Published: 2026-05-21T08:59:23.498Z

35521-4 is a LOINC code used to identify Clinical trial protocol Direct access to source data+documents section 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 Direct access to source data+documents section. It is commonly used with the system or sample type ^Clinical trial protocol.

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 Direct access to source data+documents section. It is commonly used with the system or sample type ^Clinical trial protocol.

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

What it does not mean

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

Key facts

Clinical trial protocol Direct access to source data+documents section
Direct access to source data+documents section
CTP; Dir; Direct access to source data+docs; DOCUMENT.REF; DOCUMENT.REF.CTP; Narrative; Report; Srce

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

Clinical trial protocol Direct access to source data+documents sectionCTP Direct access to source data+docsDirect access to source data+documents sectionDOC.REF.CTP-^Clinical trial protocolNar

Frequently asked questions

Code details

Code35521-4

SystemLOINC

Display nameClinical trial protocol Direct access to source data+documents section

DescriptionDirect access to source data+documents section

Short nameCTP Direct access to source data+docs

ComponentDirect access to source data+documents section

Property-

Timing-

System (specimen)^Clinical trial protocol

ScaleNar

ClassDOC.REF.CTP

StatusACTIVE

Flags

BillableNo

Valid clinical useNo

Source

SourceLOINC

Version2.82

Releasemain

First released2.13

Last changed2.27

Part names

Direct access to source data+documents section-^Clinical trial protocolNar

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.