Arbitrary activity (arb.act.) - Dynamic NPU Manual
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# Arbitrary activity (arb.act.)

Arb.act.

### Definition in words

1. Arbitrary activity of component B in system 1 (Ratio scale)
2. Arbitrary activity of component B in system 1 compared with arbitrary activity of component B in reference system (Ordinal scale)

Note 1:The concept has two definitions.

Note 2: “Activity” is an kind-of-quantiy related to rate. Cannot be related to catalytic-activity. For kind-of-quantity related to catalytic-activity, see Arbitrary catalytic-activity or Arbitrary catalytic-activity concentration.

Note 3: The reference is defined by the laboratory.

### Systematic terms

Arbitrary activity of component B in system 1

### Result type

Ordinal scale
• Value set is ranked accoding to magnitude
• The value set and the limit of the value set are defined by the laboratory
• The value set can be either numerical values or words.

Example 1

Value set={none < some < high < very high}

Example 2

Value set={low < normal< high }

Example 3

Value set={0 < 1 < 2}

Example 4

Value set={negative < positive}

Example 5

Value set={+ < ++ < +++}

• Algebraic operations are not allowed (Ref. 2, 1.26)
• Possible comparison of values (a<b, a=b or a>b)
Rational scale
• Value sets are positive numerical values
• Numerical values from 0-∞
• Algebraic operations are allowed
• Possible comparison of values (a=nb; a≠nb)

### Unit

International unit (IU) or procedure defined unit (p.d.u.) (non-SI units)

### Special rule(s) in the NPU syntax

“Procedure” is stated in the specification to the kind-of-property in the NPU definition.

“Procedure” indicates that the measurement procedure must be stated somewhere else than the NPU code and there may be difficulties in comparing values for the same NPU code.

If the ratio scale is attributed to the NPU definition, the unit can be a non-SI unit.

If the unit is an International Unit (IU), an international certified reference material (e.g. WHO reference material) is specified in the specification to the kind-of-property.

If there exist no international certified reference material, the laboratory can specify the unit at the placeholder, procedure defined unit.

If ordinal scale is attributed, no unit is stated.

### Reference

1. Ferard G, Dybkaer R, Fuentes-Arderiu X. Compendium of Terminology and Nomenclature of Properties in Clinical Laboratory Sciences : Recommendations 2016. 1 ed: Royal Society of Chemistry; 2016. 182 p.
2. Mesures BIdPe. International Vocabulary of Metrology – Basic and General Concepts and Associated Terms VIM 3rd edition JCGM 200:2012 (JCGM 200:2008 with minor corrections). https://www.bipm.org: Bureau International des Poids et Mesures; 2008.

### Molecular Biology and Genetics

Example 1 (ordinal)
Generic abbreviated form NPU02205 Ercs(B)—Glucose-6-phosphate dehydrogenase; arb.act.(proc.) = ?
Full form with a result NPU02205 Erythrocytes(Blood)—Glucose-6-phosphate dehydrogenase; arbitrary activity(procedure) = high
Abbreviated form with a result NPU02205 Ercs(B)—Glucose-6-phosphate dehydrogenase; arb.act.(proc.) = high
Written expression The arbitrary activity of Glucose-6-phosphate dehydrogenase of erythrocytes in Mr Smith’s blood is [high], compared with the arbitrary activity of Glucose-6-phosphate dehydrogenase of erythrocytes in a reference system. The measurement is performed according to a procedure defined by the laboratory,
Notes
1. The reference is defined by the laboratory.
2. “High” is a value according to a value set defined by the laboratory.

### Thrombosis and Haemostasis

Example 2 (ratio)
Generic abbreviated form NPU27758 Trcs(B)—Aggregation, ADP-induced; arb.act.(proc.) = ?
Full form with a result NPU27758 Thrombocytes(Blood)—Aggregation, ADP-induced; arbitrary activity(procedure) = 500 AUC
Abbreviated form with a result NPU27758 Trcs(B)—Aggregation, ADP-induced; arb.act.(proc.) = 500 AUC
Written expression The arbitrary activity of Aggregation, ADP-induced of thrombocytes in Mr Smith’s blood is [500] AUC. The measurement is performed according to a procedure defined by the laboratory,
Equation
Notes

“AUC” was chosen by a local laboratory as a proprietary measurement unit.

It must be emphasized that “AUC” or other types of procedure defined units are not accepted international units.

Example 3 (ordinal)
Generic abbreviated form NPU26883 B—Coagulation; arb.act.(thrombelastography) = ?
Full form with a result NPU26883 Blood—Coagulation; arbitrary activity(thrombelastography) = normal
Abbreviated form with a result

NPU26883 B—Coagulation; arb.act.(thrombelastography) = normal

Written expression The arbitrary activity of Coagulation in Mr Smith’s blood is [normal], compared with the arbitrary activity of Coagulation in in a reference system. The measurement is performed according to a thrombelastography procedure defined by the laboratory,
Notes
1. The reference is defined by the laboratory.
2. “High” is a value according to a value set defined by the laboratory.

### Reference

NPU database, https://www.ifcc.org/ifcc-scientific-division/sd-committees/c-npu/npusearch/ and http://www.labterm.dk/default.aspx
• # Kind-of-property

• ## Kind-of-quantity

### Reference

• Dybkaer R. Concept system on ‘quantity’: formation and terminology. Accredit Qual Assur. 2013;18(3):253-60.
• Dybkaer R. ISO terminological analysis of the VIM3 concepts ‘quantity’ and ‘kind-of-quantity’. Metrologia. 2010;47(3):127-34.
Date Term Note Reference
1996-01-01 Arbitrary activity Term established. NPU database, https://www.ifcc.org/ifcc-scientific-division/sd-committees/c-npu/npusearch/ and http://www.labterm.dk/default.aspx
 NPU term identifier QU50118