E - Examples for LOINC Property Matching

Content (Cnt)

Like concentration except that volume in the denominator is replaced by mass. By extension:

CCnt

Catalytic Content, catalytic activity of a component per unit mass of a sample (System).

24048-1|Alpha galactosidase:CCnt:Pt:Fib:Qn

MCnt

Mass Content, mass of component per unit mass of a sample (System).

9435-9|Isopropanol:MCnt:Pt:Tiss:Qn

Note
All of the heavy metal measurements in hair, nails, and tissue should all be mass contents.

8157-0|Arsenic:MCnt:Pt:Nail:Qn

NCnt

Number Content, number of component entities per unit mass of a sample (System).

20771-2|Coliform bacteria:NCnt:Pt:Egg:Qn:Viability count

Note
CSF/Serum Protein calculation is not a ratio, because the measured components are not in the same system. Its Property type is relative mass concentration, RelMCnc (see below).

Note
If the units of the denominator and numerator are both mass (e.g., mg/g), use MRto: 13719-0|Carnitine/Creatinine:MRto:Pt:Urine:Qn

If the units of the denominator and numerator are both substance (e.g., mmol/mol) use SRto:
22695-1|Carnitine/Creatinine:SRto:Pt:Urine:Qn

If the units of the denominator and numerator are different (mmol/g), use Ratio: 17866-5|Carnitine/Creatinine:Ratio:Pt:Urine:Qn

Fraction (Fr)

Fraction of component A in a group of entities B, C, Y, N in system 1. By extension:

CFr

Catalytic Fraction

2536-1|Lactate dehydrogenase1/Lactate dehydrogenase.total:CFr:Pt:Ser/Plas:Qn:Electrophoresis
9642-0|Creatine Kinase.BB/Creatine kinase.total:CFr:Pt:Ser/Plas:Qn

NFr

Number Fraction

10602-1|Spermatozoa.abnormal head/100 spermatozoa:NFr:Pt:Semen:Qn
764-1|Neutrophils.band form/100 leukocytes:NFr:Pt:Bld:Qn:Manual count

MFr

Mass Fraction

2614-6|Methemoglobin/Hemoglobin.total:MFr:Pt:Bld:Qn

SFr

Substance Fraction

30192-9|Acetylcholine receptor modulation Ab/Acetylcholine Ab.total:SFr:Pt:Ser:Qn

VFr

Volume Fraction

4545-0|Hematocrit:VFr:Pt:Bld:Qn:Spun

Ratio (Rto)

Ratio of component A to component B in system 1. By extension:

CRto

Catalytic Ratio (previously Catalytic Concentration Ratio, CCRto)

2325-9|Gamma glutamyl transferase/Aspartate aminotransferase:CRto:Pt:Ser/Plas:Qn

SRto

Substance Ratio (previously Substance Concentration Ratio, SCRto)

2958-7|Sodium/Potassium:SRto:Pt:Sweat:Qn

MRto

Mass Ratio (previously Mass Concentration Ratio, MCRto)

2768-0|Phenylalanine/Tyrosine:MRto:Pt:Ser/Plas:Qn

NRto

Number Ratio

11138-5|Myeloid cells/Erythroid cells:NRto:Pt:Bone mar:Qn

VelRto

Velocity Ratio

12022-0|Resistivity index:VelRto:Pt:Uterine artery.right:Qn:Doppler.calculated

VRatRto

Volume Rate Ratio

29462-9|Pulmonic flow/Systemic flow:VRatRto:Pt:Circulatory system.XXX:Qn:US.doppler

Ratio

1811-9|Amylase/Creatinine renal clearance:Ratio:24H:Urine:Qn

Note
CSF/Serum Protein calculation is not a ratio, because the measured components are not in the same system. Its Property type is relative mass concentration, RelMCnc(see below).

Note
If the units of the denominator and numerator are both mass (e.g., mg/g), use MRto:

13719-0|Carnitine/Creatinine:MRto:Pt:Urine:Qn

If the units of the denominator and numerator are both substance (e.g., mmol/mol) use SRto:

22695-1|Carnitine/Creatinine:SRto:Pt:Urine:Qn

If the units of the denominator and numerator are different (mmol/g), use Ratio:

17866-5|Carnitine/Creatinine:Ratio:Pt:Urine:Qn

Relative (Rel)

Relative amount of component A in system 1 compared to system 0. By extension:

REL should be used anywhere an actual measurement is divided by a measurement on a normal or control. It should also be used when a quotient is created by dividing a measured substance in Serum by the same substance measured in CSF, Urine, etc.

RelMCnc

Relative Mass Concentration (as noted previously)

2858-9|Protein.CSF/Protein.serum:RelMCnc:Pt:Ser+CSF:Qn
3235-9|Coagulation factor XII Ag actual/Normal:RelMCnc:Pt:PPP:Qn:Imm

RelTime

Relative time

3232-6|Coagulation factor XII activity actual/Normal:RelTime:Pt:PPP:Qn:Coag

RelCCnc

Relative Catalytic Concentration

28660-9|Plasminogen actual/Normal:RelCCnc:Pt:PPP:Qn:Chromo

RelRto

Relative Ratio

1756-6|Albumin.CSF/Albumin.SerPl:RelRto:Pt:Ser/Plas+CSF:Qn

RelVol

Relative Volume

19853-1|Capacity.inspiratory.bs/Capacity.inspiratory.preop:RelVol:Pt:Respiratory system:Qn:Spirometry

RelVrat

Relative Volume Rate

20161-6|Voluntary ventilation.max^postbronchodilator/MVV:predicted:RelVRat:Pt:Respiratory system:Qn

Complex (Cmplx)

Other divisions of one measurement by another that are not covered by the above rules should be classed as having Complex (Cmplx) properties, and the exact formula for deriving the quantity should be explicitly stated.

Arbitrary (Arb)

Arbitrary concentration of items. If we are not measuring the activity of an enzyme then the units of measure and properties are as follows. Note that U is reserved for catalytic properties (see box below).

Possible Values Property Scale
arb U/min, IU/24hr, etc. ARat Qn
Unitless (Patient/Control), % AFr Qn
arb U/gm, IU/gm, etc. ACnt Qn
arb U/mL, IU/mL, etc. ACnc Qn

Note
If we are measuring the activity of an enzyme then the units of measure and properties are:

Possible Values Property Scale
U/mL, Units/mL, etc. CCnc Qn
U/gm, Units/gm, etc. CCnt Qn
U/24hr, Unit/min, etc. CRat Qn
Unitless (Patient/Control) CFr Qn

If the Property is Titr then the Scale is always Qn

For any X Ab or Ag:

Possible Values Property Scale
<1:2, 1:4, 1:8... Titr Qn

For Any X Ab or Ag

Possible Values Property Scale
Neg, Indeterminate, Pos PrThr Ord
1+, 2+, 3+... PrThr Ord
<1:2, 1:4, 1:8... Titr Qn
Neg, 1:4, 1:8... Titr Qn
Neg, 0.90... ACnc Qn (EIA units)

Nominal (Nom)

For any intensive evaluation whose value comes from a finite set of unranked (independent) coded items, the Property will be Prid (or Type) and Scale Nom. Prid is used in cases where the value set includes the option of reporting “none”, “not present”, etc. Type is used in cases where the result always specifies a value from the finite set. For extensive measures whose value comes from a finite set of unranked coded items, the Property will be the extensive property, and the Scale will be Nom.

Intensive Properties Possible Values (coded) Property Scale
Organism Identified E. coli, S. aureus, etc. Prid Nom
ABO Group A, B, AB, O Type Nom
Surgery (Dis. Summary) Cholecystectomy, Appendectomy Prid Nom
Extensive Properties Possible Values (coded) Property Scale
Urine Color Amber, straw, etc. Type Nom

Narrative (Nar)

For any intensive evaluation whose value comes from a finite set of unranked (independent) free text items (or a paragraph), the Property will be Prid or Find, and the scale will be Nar to indicate that the result is free text narrative. For extensive measures whose value comes from a finite set of unranked text items (or a paragraph), the Property will be the extensive property, and the Scale will be Nar.

Intensive Properties Possible Values (coded) Property Scale
Organism Identified E. coli, S. aureus, etc. Prid Nar
ABO Group A, B, AB, O Type Nar
Surgery (Dis. Summary) Cholecystectomy Prid Nar
Extensive Properties Possible Values (coded) Property Scale
Urine Color Amber, straw, etc. Type Nar

Impression or Interpretation (Imp)

Imp is used to represent the Property when the evaluation is a mental abstraction based on one a collection of measurements and/or data. For example, if several measurements are made relative to immunoglobin levels in Serum and CSF in a myasthenia gravis panel, and if by examining all of the evidence a pathologist decided that this pattern of findings represented active disease (which could be represented as a coded value), the result of the pathologist thought process would be represented as:

Evaluation Possible Values (text) Property Scale
Myasthenia Evaluation No disease, chronic disease Imp Nom

If the pathologist evaluation is reported free text or a paragraph of information, the representation would be:

Evaluation Possible Values (text) Property Scale
Myasthenia Evaluation No disease, chronic disease Imp Nar

Method versus Property

Be careful in distinguishing end point detection method from Property. For example, if sodium is measured using an ion specific electrode, the Property is not a voltage difference. The voltage difference is just a method for indirectly measuring the sodium concentration. Concentration is the real Property. Likewise, many antigens and antibodies are now measured using optical density as the detection method. However, the Property we are really measuring is an arbitrary concentration (ACnc), not the optical density. If it is a ratio of optical densities (as with Gliadin Ab, Parvovirus B19 Ab, etc.) that are compared (patient value divided by a standard control), then the Property should be RelACnc (relative arbitrary concentration).

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