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.

LOINCActiveBoth

LOINC Code 73978-9: vWf.activity IA Qn (PPP)

Name: LOINC Code 73978-9: vWf.activity IA Qn (PPP)
Creator: HealthAssure Clinical Team
Published: 2026-05-21T08:59:53.972Z

73978-9 is a LOINC code used to identify vWf.activity IA Qn (PPP) 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 von Willebrand factor.activity. It is commonly used with the system or sample type PPP.

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 von Willebrand factor.activity. It is commonly used with the system or sample type PPP.

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: Both
Method: IA

What it does not mean

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

Key facts

von Willebrand factor (vWf).activity [Units/volume] in Platelet poor plasma by Immunoassay

von Willebrand factor.activity

Von Willebrand Factor Activity (VWF Activity, vWFAct) in plasma specimens can be quantitatively determined by immunological methods. This code is created for, but not limited in use to, the submitter's kit, HemosIL Von Willebrand Factor Activity Kit, which determines VWF activity by measuring the increase of turbidity produced by the agglutination of the latex reagent. This assay uses a specific anti-VWF monoclonal antibody directed against the platelet binding site of VWF, glycoprotein Ib receptor, and reacts with the VWF in patient plasma. The degree of agglutination is directly proportional to the activity of VWF in the sample and is determined by measuring the decrease of transmitted light caused by the aggregates. The submitter's lab reports the results in U/mL where U represents "units" rather than the standard meaning of U, which is mmol/Min, a measure of enzyme rates. Additional testing (e.g. ristocetin cofactor assay) may be needed to confirm a diagnosis of von Willebrand disease (VWD).

Activ; Actvty; Arbitrary concentration; COAGULATION; EIA; ELFA; ELISA; Enzyme immunoassay; Fac; Fact; Hematology; Heme; IAA; MEIA; Movements; Plas; Platelet poor plasma; Point in time; QNT; Quan; Quant; Quantitative; Random; SUDS; Von will; Vonwillebrand; vWf; vWfAc

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

vWf.activity IA Qn (PPP)von Willebrand factor (vWf).activity [Units/volume] in Platelet poor plasma by ImmunoassayvWf:Ac PPP IA-aCncvon Willebrand factor.activityCOAGvWf.activity, BloodACnc

Frequently asked questions

Code details

Code73978-9

SystemLOINC

Display namevWf.activity IA Qn (PPP)

Descriptionvon Willebrand factor.activity

Short namevWf:Ac PPP IA-aCnc

Componentvon Willebrand factor.activity

PropertyACnc

TimingPt

System (specimen)PPP

ScaleQn

MethodIA

ClassCOAG

Example unitsarb U/mL

StatusACTIVE

Order/ObservationBoth

Flags

BillableNo

Valid clinical useNo

Source

SourceLOINC

Version2.82

Releasemain

First released2.44

Last changed2.73

Consumer names

vWf.activity, Blood

Part names

von Willebrand factor.activityACncPtPPPQnIAvon Willebrand factor (vWf).activityArbitrary ConcentrationPoint in time (spot)Platelet poor plasmaImmunoassay

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.