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.

LOINCActiveOrder

LOINC Code 74545-5: Tryptophan-related indole profiling panel (PRP)

Name: LOINC Code 74545-5: Tryptophan-related indole profiling panel (PRP)
Creator: HealthAssure Clinical Team
Published: 2026-05-21T08:59:53.976Z

74545-5 is a LOINC code used to identify Tryptophan-related indole profiling panel (PRP) 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 Tryptophan-related indole profiling panel. It is commonly used with the system or sample type PRP.

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 Tryptophan-related indole profiling panel. It is commonly used with the system or sample type PRP.

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: Order
Panel type: Panel

What it does not mean

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

Key facts

Tryptophan-related indole profiling panel - Platelet rich plasma

Tryptophan-related indole profiling panel

Profiling of the plasma indoles tryptophan, 5-hydroxytryptophan (5-HTP), 5-Hydroxytryptamine (serotonin), and 5-hydroxyindoleacetic acid (5-HIAA) is useful in the diagnosis of carcinoid tumors with symptoms suggestive of carcinoid syndrome. Platelet serotonin is the most sensitive indole marker for the diagnosis and follow-up of carcinoids. In contrast to urinary 5-HIAA, platelet serotonin is not influenced by dietary intake of foods containing serotonin. [PMID11568091]

c244; Chemistry; L-tryptophan; Pan; PANEL.CHEMISTRY; Panl; Platelet rich plasma; Pnl; Point in time; Random; Trp; Tryp-related indole profile pnl

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

Tryptophan-related indole profiling panel (PRP)Tryptophan-related indole profiling panel - Platelet rich plasmaTryp-related indole profile pnl PRPTryptophan-related indole profiling panelPANEL.CHEMTryptophan-related indole profiling panel, Blood-

Frequently asked questions

Code details

Code74545-5

SystemLOINC

Display nameTryptophan-related indole profiling panel (PRP)

DescriptionTryptophan-related indole profiling panel

Short nameTryp-related indole profile pnl PRP

ComponentTryptophan-related indole profiling panel

Property-

TimingPt

System (specimen)PRP

Scale-

ClassPANEL.CHEM

StatusACTIVE

Order/ObservationOrder

Flags

BillableNo

Valid clinical useNo

Source

SourceLOINC

Version2.82

Releasemain

First released2.48

Last changed2.48

Consumer names

Tryptophan-related indole profiling panel, Blood

Part names

Tryptophan-related indole profiling panel-PtPRPPoint in time (spot)Platelet rich 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.