Abstract
Three interlaboratory round-robin studies (RR1, RR2, and RR3) were conducted to identify a serum-based reference material that would aid in the standardization of direct ion-selective electrode (ISE) measurements of sodium and potassium. Ultrafiltered frozen serum reference materials requiring no reconstitution reduced between-laboratory variability (the largest source of imprecision) more than did other reference materials. ISE values for RR3 were normalized by the use of two points at the extremes of the clinical range for sodium (i.e., 120 and 160 mmol/L), with values assigned by the flame atomic emission spectrometry (FAES) Reference Method. This FAES normalization of ISE raw values remarkably improved all sources of variability and unified the results from seven different direct ISE analyzers to the FAES Reference Method value. Subsequently, a three-tiered, fresh-frozen human serum reference material was produced to the specifications developed in RR1-RR3, was assigned certified values for sodium and potassium by Definitive Methods at the National Institute of Standards and Technology (NIST), and was made available in 1990 to the clinical laboratory community as a Standard Reference Material (SRM); it is now identified as SRM 956. Albeit retrospectively, we show how applying an FAES normalization step identical to that used in RR4/5 to the ISE data for SRM 956 after the NIST Definitive Method values were known, consistently moved the ISE results for RR3 closer to the true value for Na+ and K+.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 1459-1465 |
| Number of pages | 7 |
| Journal | Clinical Chemistry |
| Volume | 38 |
| Issue number | 8 |
| State | Published - 1992 |
| Externally published | Yes |
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Keywords
- Definitive method-assigned values
- Electrolytes
- Flame atomic emission spectrometry
- National reference system
- Reference material
ASJC Scopus subject areas
- Clinical Biochemistry
Cite this
Frozen human serum reference material for standardization of sodium and potassium measurements in serum or plasma by ion-selective electrode analyzers. / Gunaratna, Prema C.; Koch, William F.; Paule, Robert C.; Cormier, Alan D.; D'Orazio, Paul; Greenberg, Neil; O'Connell, Kathleen M.; Malenfant, Arthur; Okorodudu, Anthony; Miller, Richard; Kus, Debra M.; Bowers, George N.
In: Clinical Chemistry, Vol. 38, No. 8, 1992, p. 1459-1465.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Frozen human serum reference material for standardization of sodium and potassium measurements in serum or plasma by ion-selective electrode analyzers
AU - Gunaratna, Prema C.
AU - Koch, William F.
AU - Paule, Robert C.
AU - Cormier, Alan D.
AU - D'Orazio, Paul
AU - Greenberg, Neil
AU - O'Connell, Kathleen M.
AU - Malenfant, Arthur
AU - Okorodudu, Anthony
AU - Miller, Richard
AU - Kus, Debra M.
AU - Bowers, George N.
PY - 1992
Y1 - 1992
N2 - Three interlaboratory round-robin studies (RR1, RR2, and RR3) were conducted to identify a serum-based reference material that would aid in the standardization of direct ion-selective electrode (ISE) measurements of sodium and potassium. Ultrafiltered frozen serum reference materials requiring no reconstitution reduced between-laboratory variability (the largest source of imprecision) more than did other reference materials. ISE values for RR3 were normalized by the use of two points at the extremes of the clinical range for sodium (i.e., 120 and 160 mmol/L), with values assigned by the flame atomic emission spectrometry (FAES) Reference Method. This FAES normalization of ISE raw values remarkably improved all sources of variability and unified the results from seven different direct ISE analyzers to the FAES Reference Method value. Subsequently, a three-tiered, fresh-frozen human serum reference material was produced to the specifications developed in RR1-RR3, was assigned certified values for sodium and potassium by Definitive Methods at the National Institute of Standards and Technology (NIST), and was made available in 1990 to the clinical laboratory community as a Standard Reference Material (SRM); it is now identified as SRM 956. Albeit retrospectively, we show how applying an FAES normalization step identical to that used in RR4/5 to the ISE data for SRM 956 after the NIST Definitive Method values were known, consistently moved the ISE results for RR3 closer to the true value for Na+ and K+.
AB - Three interlaboratory round-robin studies (RR1, RR2, and RR3) were conducted to identify a serum-based reference material that would aid in the standardization of direct ion-selective electrode (ISE) measurements of sodium and potassium. Ultrafiltered frozen serum reference materials requiring no reconstitution reduced between-laboratory variability (the largest source of imprecision) more than did other reference materials. ISE values for RR3 were normalized by the use of two points at the extremes of the clinical range for sodium (i.e., 120 and 160 mmol/L), with values assigned by the flame atomic emission spectrometry (FAES) Reference Method. This FAES normalization of ISE raw values remarkably improved all sources of variability and unified the results from seven different direct ISE analyzers to the FAES Reference Method value. Subsequently, a three-tiered, fresh-frozen human serum reference material was produced to the specifications developed in RR1-RR3, was assigned certified values for sodium and potassium by Definitive Methods at the National Institute of Standards and Technology (NIST), and was made available in 1990 to the clinical laboratory community as a Standard Reference Material (SRM); it is now identified as SRM 956. Albeit retrospectively, we show how applying an FAES normalization step identical to that used in RR4/5 to the ISE data for SRM 956 after the NIST Definitive Method values were known, consistently moved the ISE results for RR3 closer to the true value for Na+ and K+.
KW - Definitive method-assigned values
KW - Electrolytes
KW - Flame atomic emission spectrometry
KW - National reference system
KW - Reference material
UR - http://www.scopus.com/inward/record.url?scp=0026709040&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0026709040&partnerID=8YFLogxK
M3 - Article
VL - 38
SP - 1459
EP - 1465
JO - Clinical Chemistry
JF - Clinical Chemistry
SN - 0009-9147
IS - 8
ER -