73978-9

LOINC Code


LOINC code73978-9
name
descriptionVon Willebrand Factor Activity (VWF Activity, vWF:Act) 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).
statusACTIVE

Fully-Specified Name

componentvon Willebrand factor.activity
propertyACnc  =  Arbitrary Concentration
timePt  =  Point in time:  To identify measures at a point in time. This is a synonym for “spot” or “random” as applied to urine measurements.
systemPPP  =  Platelet poor plasma
scaleQn  =  Quantitative:  The result of the test is a numeric value that relates to a continuous numeric scale. Reported either as an integer, a ratio, a real number, or a range. The test result value may optionally contain a relational operator from the set {<=, <, >, >=}. Valid values for a quantitative test are of the form "7", "-7", "7.4", "-7.4", "7.8912", "0.125", "<10", "<10.15", ">12000", 1-10, 1:256
methodIA  =  Immunoassay:  Encompasses all immunoassays with a few exceptions, including Immune Blot and Immune Fluorescence, which were created based on historic usage.

Additional Names

short nameActiv; 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;

Basic Attributes

classCOAG
type1  Laboratory
order vs. observationvWf:Ac PPP IA-a
example UCUM unitsarb U/mL
The Unified Code for Units of Measure (UCUM) is a code system intended to include all units of measures being contemporarily used in international science, engineering, and business (www.unitsofmeasure.org)

History/Usage

first released
last updated2.73
last change typeMIN  - change to field other than name
change reason[arb'U]/mL

Related Names



Copyright © 2026 Regenstrief Institute, Inc. All Rights Reserved. To the extent included herein, the LOINC table and LOINC codes are copyright © 1995-2026, Regenstrief Institute, Inc. and the Logical Observation Identifiers Names and Codes (LOINC) Committee. See https://loinc.org/license for the full LOINC copyright and license.

demo
request yours today
subscribe
start today
newsletter
free subscription

Thank you for choosing Find-A-Code, please Sign In to remove ads.

Aimee- AI -powered coding assistant - Try it now for Free Would you like Aimee - AI
to help you with this?