LOINCActiveObservation

LOINC Code 18864-9: Ampicillin [Susc]

18864-9 is a LOINC code used to identify Ampicillin [Susc] 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 Ampicillin. It is commonly used with the system or sample type Isolate.

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 Ampicillin. It is commonly used with the system or sample type Isolate.

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: Observation

What it does not mean

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

Key facts

  • Ampicillin [Susceptibility]
  • Ampicillin
  • Amcil; Amicil; Amp; Ampicilloyl; ANTIBIOTIC SUSCEPTIBILITIES; AST; c203; c5; ID; Infectious Disease; InfectiousDisease; Islt; Isol; Omnipen; Penbritin; Point in time; Polycillin; Random; Sus; Suscept; Susceptibilities; Susceptibility; Susceptibilty

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

Ampicillin [Susc]Ampicillin [Susceptibility]Ampicillin Susc IsltAmpicillinABXBACTSusceptibility to AmpicillinSusc

Frequently asked questions

Code details

Code18864-9
SystemLOINC
Display nameAmpicillin [Susc]
DescriptionAmpicillin
Short nameAmpicillin Susc Islt
ComponentAmpicillin
PropertySusc
TimingPt
System (specimen)Isolate
ScaleOrdQn
ClassABXBACT
StatusACTIVE
Order/ObservationObservation

Flags

BillableNo
Valid clinical useNo

Source

SourceLOINC
Version2.82
Releasemain
First released1.0l
Last changed2.73

Consumer names

Susceptibility to Ampicillin

Part names

AmpicillinSuscPtIsolateOrdQnSusceptibility (microorganisms)Point in time (spot)

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.

LOINC Code 18864-9 | HealthAssure