von Willebrand factor (vWf) ristocetin cofactor/von Willebrand factor (vWf) Ag [Ratio] in Platelet poor plasma 81643-9
LOINC Code
| LOINC code | 81643-9 | ||
|---|---|---|---|
| name | von Willebrand factor (vWf) ristocetin cofactor/von Willebrand factor (vWf) Ag [Ratio] in Platelet poor plasma | ||
| description | This term represents a ratio of two results that are expressed as percentages of normal: the von Willebrand factor.ristocetin cofactor activity and the von Willebrand factor antigen concentration, both of which are reported as actual/Normal. The von Willebrand factor (vWF) ristocetin cofactor activity to antigen ratio can help distinguish different types of von Willebrand disease (VWD). VWD types 1 and 3 are usually associated with a quantitative decrease in vWF, which would affect both the vWF ristocetin cofactor activity as well as vWF antigen concentration, while type 2 is associated with a functional defect in VWF, which would affect the activity but not the amount of antigen present. Therefore, patients with type 2 VWD are likely to have a lower vWF ristocetin cofactor activity to antigen ratio (less than 0.6-0.7) compared to patients with types 1 or 3 VWD. | ||
| status | ACTIVE | ||
Fully-Specified Name | |||
| component | von Willebrand factor.ristocetin cofactor activity/von Willebrand factor Ag | ||
| property | Ratio | ||
| time | Pt = Point in time: To identify measures at a point in time. This is a synonym for “spot” or “random” as applied to urine measurements. | ||
| system | PPP = Platelet poor plasma | ||
| scale | Qn = 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 | ||
| method | |||
Additional Names | |||
| short name | vWf:RCo/vWF Ag PPP-Rto | ||
Basic Attributes | |||
| class | COAG | ||
| type | 1 Laboratory | ||
| order vs. observation | Both | ||
| formula (readable) | (vWF ristocetin cofactor activity actual/Normal)/(vWF Ag actual/Normal) | ||
| example UCUM units | {ratio} 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) | ||
| example unit | ratio | ||
Associated Observations | |||
LOINC codes that represent optional associated observation(s) for a clinical observation or laboratory test. A LOINC term may represent a single associated observation or panel containing several associated observations. | |||
History/Usage | |||
| test rank | 3139 of 2000 most commonly performed tests by labs in USA | ||
| first released | |||
| last updated | 2.73 | ||
| last change type | MIN - change to field other than name | ||
Related Names | |||
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