Version 2.73

77341-6Anion gap 4 in Serum, Plasma or BloodActive

Part Description

LP15392-1   Anion gap 4
Anion Gap 4 is the difference between the sum of serum sodium + serum potasium and the sum of the serum bicarbonate+ chloride. Calculated based on the concentration of four electrolytes as follows: ([Na+] + [K+]) − ([Cl−] + [HCO3−]). An increased gap indicates the presence of an unmeasured anion. Source: Regenstrief Institute

Fully-Specified Name

Anion gap 4

Additional Names

Short Name
Anion Gap4 SerPlBld-sCnc
Display Name
Anion gap 4 (S/P/Bld) [Moles/Vol]
Consumer Name Alpha
Anion gap 4, Blood

Basic Attributes

First Released
Version 2.52
Last Updated
Version 2.68
Change Reason
Release 2.68: DefinitionDescription: Moved to Mapping Guidance section.; Previous Releases: Changed the method from "Calculated" to methodless to fit the current LOINC model.
Order vs. Observation

Formula (Readable)

(NA+K) - (CL+CO2)=Anion Gap

Reference Information

Type Source Reference
Mapping Guidance LOINC This term was made to accommodate a laboratory system outside of the US. LOINC currently discourages the use of specimens combining ser/plas and blood in one term (as ser/plas/bld) for two reasons. First, practices usually want to distinguish the two on ordering since whole blood usually implies a point of care test and ser/plas usually implies sending to another location. Second, whole blood tests are usually classified as low complexity (waived) under CLIA regulations, and because waived tests are excluded from the annual COLA report of testing volume (required by the Centers for Medicare and Medicaid Services) and ser/plas tests are not, the two have to be distinguished.

Member of these Groups

LG6139-2 Anion gap 4|SCnc|Pt|ANYBldSerPl

Language Variants Get Info

zh-CNChinese (China)
阴离子间隙 4:物质的量浓度:时间点:血清/血浆/全血:定量型:
nl-NLDutch (Netherlands)
anion gap 4:mol/volume:moment:serum of plasma of bloed:kwantitatief:
et-EEEstonian (Estonia)
Anioonide vahe 4:SCnc:Pt:S/P/B:Qn:
fr-BEFrench (Belgium)
Trou anionique 4:Concentration de substance:Temps ponctuel:Sérum/Plasma/Sang:Quantitatif:
fr-CAFrench (Canada)
Trou anionique 4:Concentration de substance:Temps ponctuel:Sérum/Plasma/Sang:Quantitatif:
fr-FRFrench (France)
Balance ionique 4:Moles/Volume:Ponctuel:Sérum/Plasma/Sang:Numérique:
it-ITItalian (Italy)
Gap anionico 4:SCnc:Pt:Siero/Plasma/Sangue:Qn:
ru-RURussian (Russian Federation)
Анионный интервал 4:МолКонц:ТчкВрм:Сыв/Плаз/Кр:Колич:
es-MXSpanish (Mexico)
Brecha aniónica 4:Concentración de sustancias:Punto temporal:Suero, plasma o sangre:Cuantitativo:
es-ESSpanish (Spain)
Anión GAP 4:Concentración de sustancia:Punto temporal:Suero, Plasma o Sangre:Qn:
tr-TRTurkish (Turkey)
Anyon açığı 4:SubKons:Zmlı:Ser/Plaz/Kan:Kant:

Example Units

Unit Source
mmol/L Example UCUM Units

LOINC FHIR® API Example - CodeSystem Request Get Info