LOINC

LOINC Code 11955-2: Deprecated Last menstrual period

11955-2 is a LOINC code used to identify Deprecated Last menstrual period 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 Last menstrual period. It is commonly used with the system or sample type ^Patient.

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 Last menstrual period. It is commonly used with the system or sample type ^Patient.

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: DEPRECATED
  • Method: Reported

What it does not mean

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

Key facts

  • Deprecated Last menstrual period
  • Last menstrual period
  • First day of last menstrual period reported by patient.
  • Date and time; Gyn; Gynecology; LMP; OB; ObGyn; OBSTERICAL; OBSTERICAL.ULTRASOUND; Obstetrical; Obstetrics; Past; Point in time; QNT; Quan; Quant; Quantitative; Random; Time stamp; Timestamp

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

Deprecated Last menstrual periodDeprecatedLast menstrual periodLast menstrual periodOB.USTmStpPt^Patient

Frequently asked questions

Code details

Code11955-2
SystemLOINC
Display nameDeprecated Last menstrual period
DescriptionLast menstrual period
Short nameDeprecatedLast menstrual period
ComponentLast menstrual period
PropertyTmStp
TimingPt
System (specimen)^Patient
ScaleQn
MethodReported
ClassOB.US
StatusDEPRECATED

Flags

BillableNo
Valid clinical useNo

Source

SourceLOINC
Version2.82
Releasemain
First released1.0j-a
Last changed2.36

Part names

Last menstrual periodTmStpPt^PatientQnReportedTime Stamp (Date and Time)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 11955-2 | HealthAssure