CCQM-K159
MEASURAND Mass fraction of DL-Phenylalanine in human plasma
NOMINAL RANGE 1 mg/kg to 1000 mg/kg
Degrees of equivalence represented by Di = (xI - xR) and its expanded uncertainty Ui at a 95 % level of confidence, both expressed in mg/kg.
CCQM-K159
MEASURAND Mass fraction of DL-Phenylalanine in human plasma
NOMINAL RANGE 1 mg/kg to 1000 mg/kg
Degrees of equivalence represented by Di = (xI - xR) and its expanded uncertainty Ui at a 95 % level of confidence, both expressed in mg/kg.
| LABi | Di | Uneg,i | Upos,i | |
|---|---|---|---|---|
mg/kg |
mg/kg |
mg/kg |
||
| UME | -2.672 | 3.942 | ||
| VNIIM | -1.822 | 3.262 | ||
| LGC | -0.732 | 1.438 | ||
| EXHM/GCSL-EIM | -0.582 | 4.130 | ||
| NMIJ | -0.222 | 0.750 | ||
| NIMT | -0.022 | 2.324 | ||
| PTB | 0.128 | 1.348 | ||
| INMETRO | 0.378 | 2.510 | ||
| HSA | 0.488 | 1.638 | ||
| NMIA | 1.078 | 1.730 | ||
| KRISS | 1.158 | 1.402 |
| Metrology area, Sub-field | Chemistry and Biology, Organics |
| Description | Free amino acids in human plasma |
| Time of measurements | 2020 - 2021 |
| Status | Approved for equivalence |
| Final Reports of the comparisons | |
| Measurand | Mass fraction of DL-Phenylalanine in mg/kg 1 mg/kg to1000 mg/kg |
| Comparison type | Key Comparison |
| Consultative Committee | CCQM (Consultative Committee for Amount of Substance) |
| Conducted by | CCQM (Consultative Committee for Amount of Substance) |
| Comments | Inherited metabolic disorders affect approximately 1 in 1000 babies; amino acid disorders are less frequent at approximately 1 in 6000. Babies diagnosed with amino acid disorders require regular monitoring of free amino acid concentrations in blood, especially for a disease such as phenylketonuria. In addition, amino acid measurement may aid in the evaluation of several other disorders such as neurological and nutritional disorders. Free amino acids in healthy patients are typically in the low mg/kg range but, for example, elevated phenylalanine indicates phenylketonuria disease state. Evidence of successful participation in formal, relevant international comparisons is needed to document measurement capability claims (CMCs) made by national metrology institutes (NMIs) and designated institutes (DIs). |
| Pilot institute |
LGC
Laboratory of the Government Chemist United Kingdom |
| Contact person | Emily Whyte 07794157354 |
| Pilot laboratory | |
|---|---|
| LGC |
Laboratory of the Government Chemist, United Kingdom, EURAMET |
| EXHM/GCSL-EIM |
National Laboratory of Chemical Metrology/GCSL - Hellenic Institute of Metrology, Greece, EURAMET |
| HSA |
Health Science Authority, Singapore, APMP |
| INMETRO |
Instituto Nacional de Metrologia, Qualidade e Tecnologia, Brazil, SIM |
| KRISS |
Korea Research Institute of Standards and Science, Korea, Republic of, APMP |
| NIMT |
National Institute of Metrology (Thailand), Thailand, APMP |
| NMIA |
National Measurement Institute, Australia, Australia, APMP |
| NMIJ AIST |
National Metrology Institute of Japan, Japan, APMP |
| PTB |
Physikalisch-Technische Bundesanstalt, Germany, EURAMET |
| UME |
TÜBITAK Ulusal Metroloji Enstitüsü, Türkiye, EURAMET |
| VNIIM |
D.I. Mendeleyev Institute for Metrology, Rosstandart, Russian Federation, COOMET |
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CCQM-K159
MEASURAND Mass fraction of DL-Phenylalanine in human plasma
NOMINAL RANGE 1 mg/kg to 1000 mg/kg
The key comparison reference value xR and its associated standard uncertainty uR are computed from the weighted mean of the participants results as described in pages 25 to 28 of the CCQM-K159 Final report.
xR = 60.322 mg/kg uR = 0.219 mg/kg
The degree of equivalence of laboratory i relative to the key comparison reference value xR is given by a pair of terms, both expressed in mg/kg:
Di = (xi - xR) and its expanded uncertainty Ui at a 95 % level of confidence where Ui = 2 (ui2 + uR2 - 2cov(xi , xR))1/2
CCQM-K159
MEASURAND Mass fraction of DL-Phenylalanine in human plasma
NOMINAL RANGE 1 mg/kg to 1000 mg/kg
xi measured mass fraction reported by laboratory i, Labi
ui combined standard uncertainty of xi
| Labi | xi | ui | |
| mg/kg | mg/kg | ||
| UME | 57.65 | 2.06 | |
| VNIIM | 58.50 | 1.70 | |
| LGC | 59.59 | 0.72 | |
| EXHM/GCSL-EIM | 59.74 | 2.16 | |
| NMIJ | 60.10 | 0.32 | |
| NIMT | 60.30 | 1.20 | |
| PTB | 60.45 | 0.67 | |
| INMETRO | 60.70 | 1.30 | |
| HSA | 60.81 | 0.83 | |
| NMIA | 61.40 | 0.88 | |
| KRISS | 61.48 | 0.70 |
