LOINCActiveOrder

LOINC Code 78993-3: Prolactin isoforms panel

78993-3 is a LOINC code used to identify Prolactin isoforms panel 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 Prolactin isoforms panel. 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 Prolactin isoforms panel. 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: Order
  • Panel type: Panel

What it does not mean

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

Key facts

Prolactin isoforms panel - Serum or Plasma
Prolactin isoforms panel
The prolactin isoforms panel includes individual tests for monomeric, dimeric, and macroprolactin, as well as fraction terms for each isomer and an interpretation based on all of the results. Monomeric prolactin is the most common form of circulating prolactin. The dimeric form ("big-prolactin") has a molecular weight of ~50 kD, and polymeric form ("big-big prolactin") has a molecular weight of ~ 150 kD). Big-big prolactin, known as macroprolactin, and big prolactin are formed in the circulation after secretion of prolactin from the pituitary. They have a longer half-life than monomeric prolactin and are not biologically active. However, typical prolactin assays do not differentiate between the different forms of prolactin, and the presence of big and big-big prolactin can lead to a false diagnosis of hyperprolactinemia. Methods such as PEG precipitation can separate macroprolactin and big prolactin from monomeric prolactin in order to obtain a more accurate measurement of biologically active prolactin, and chromatography can be used to further characterize the isoforms if necessary. [PMCIDPMC3719302]
Chemistry; Lactotropic hormone; Lactotropin; Mammatropic hormone; Mammotropin; Pan; PANEL.CHEMISTRY; Panl; Pl; Plasma; Plsm; Pnl; Point in time; PRL; Prol; Prolactin isoforms Pnl; Random; SerP; SerPl; SerPlas; Serum; Serum or plasma; SR

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

Prolactin isoforms panelProlactin isoforms panel - Serum or PlasmaProlactin isoforms Pnl SerPlPANEL.CHEMProlactin isoforms panel, Blood-Pt

Frequently asked questions

Code details

Code78993-3
SystemLOINC
Display nameProlactin isoforms panel
Short nameProlactin isoforms Pnl SerPl
ComponentProlactin isoforms panel
Property-
TimingPt
System (specimen)Ser/Plas
Scale-
ClassPANEL.CHEM
StatusACTIVE
Order/ObservationOrder

Flags

BillableNo
Valid clinical useNo

Source

SourceLOINC
Version2.82
Releasemain
First released2.54
Last changed2.54

Consumer names

Prolactin isoforms panel, Blood

Part names

Prolactin isoforms panel-PtSer/PlasPoint 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.

LOINC Code 78993-3 | HealthAssure