Does the ID-MS traceable MDRD equation work and is it suitable for use with compensated Jaffe and enzymatic creatinine assays?

@article{citeulike:1533091, abstract = {BACKGROUND: International recommendations suggest that measurement of serum creatinine should be supplemented with an estimate of glomerular filtration rate (GFR) using the Modification of Diet in Renal Disease (MDRD) study equation. One problem has been the lack of standardization of commercially available creatinine assays resulting in varying estimates of GFR. A revision of the MDRD equation offers traceability to a reference method. This study evaluates the use of isotope dilution mass spectrometry (ID-MS), the compensated Jaffe and enzymatic creatinine methods compared with the Beckman CX3 Jaffe assay used to derive the MDRD equation and investigates their impact on GFR estimation using both the original and ID-MS-traceable MDRD equations. METHODS: Serum creatinine was measured in 277 patients by (i) ID-MS, (ii) a Roche enzymatic assay, (iii) a Roche compensated kinetic Jaffe assay and (iv) a Beckman CX3 kinetic Jaffe assay. Estimated GFR was calculated using the MDRD equations. RESULTS: The ID-MS (-7.5\%), Roche enzymatic (-8.6\%) and compensated kinetic Jaffe (-11.9\%) assays were all negatively biased (P < 0.0001) compared with the Beckman CX3 assay, causing predictable, clinically significant, overestimation of GFR when the original MDRD equation is used. This positive bias was reduced (ID-MS 6.7 to 0.4\%; enzymatic 8.8 to 3.4\%; compensated kinetic Jaffe 13.7 to 7.1\%) when GFRs were calculated using the ID-MS-traceable MDRD equation. CONCLUSIONS: Compensated assays that account for non-creatinine chromogen interference produce significantly higher estimates of GFR when using the original MDRD equation. Use of the ID-MS-traceable MDRD equation ameliorates this effect. There is good agreement between estimated GFR derived from the original MDRD equation using Beckman Astra CX3 data and estimated GFR derived from the new ID-MS-traceable MDRD equation using a local ID-MS creatinine assay. This suggests that the ID-MS-traceable MDRD equation may be reliably used with both ID-MS and true ID-MS-traceable creatinine assays without the requirement for standardization to the MDRD laboratory.}, address = {Department of Clinical Biochemistry, East Kent Hospitals NHS Trust, Kent and Canterbury Hospital, Canterbury, Kent CT1 3NG, UK. susan.vickery@ekht.nhs.uk}, author = {Vickery, S. and Stevens, P. E. and Dalton, R. N. and van Lente, F. and Lamb, E. J. }, citeulike-article-id = {1533091}, doi = {10.1093/ndt/gfl249}, issn = {0931-0509}, journal = {Nephrol Dial Transplant}, keywords = {gfr}, month = {September}, number = {9}, pages = {2439--2445}, posted-at = {2007-08-03 11:29:42}, priority = {4}, title = {Does the ID-MS traceable MDRD equation work and is it suitable for use with compensated Jaffe and enzymatic creatinine assays?}, url = {http://dx.doi.org/10.1093/ndt/gfl249}, volume = {21}, year = {2006} }

TY - JOUR ID - citeulike:1533091 L3 - citeulike-article-id:1533091 TI - Does the ID-MS traceable MDRD equation work and is it suitable for use with compensated Jaffe and enzymatic creatinine assays? JF - Nephrol Dial Transplant VL - 21 IS - 9 SP - 2439 EP - 2445 AD - Department of Clinical Biochemistry, East Kent Hospitals NHS Trust, Kent and Canterbury Hospital, Canterbury, Kent CT1 3NG, UK. susan.vickery@ekht.nhs.uk SN - 0931-0509 N2 - BACKGROUND: International recommendations suggest that measurement of serum creatinine should be supplemented with an estimate of glomerular filtration rate (GFR) using the Modification of Diet in Renal Disease (MDRD) study equation. One problem has been the lack of standardization of commercially available creatinine assays resulting in varying estimates of GFR. A revision of the MDRD equation offers traceability to a reference method. This study evaluates the use of isotope dilution mass spectrometry (ID-MS), the compensated Jaffe and enzymatic creatinine methods compared with the Beckman CX3 Jaffe assay used to derive the MDRD equation and investigates their impact on GFR estimation using both the original and ID-MS-traceable MDRD equations. METHODS: Serum creatinine was measured in 277 patients by (i) ID-MS, (ii) a Roche enzymatic assay, (iii) a Roche compensated kinetic Jaffe assay and (iv) a Beckman CX3 kinetic Jaffe assay. Estimated GFR was calculated using the MDRD equations. RESULTS: The ID-MS (-7.5%), Roche enzymatic (-8.6%) and compensated kinetic Jaffe (-11.9%) assays were all negatively biased (P < 0.0001) compared with the Beckman CX3 assay, causing predictable, clinically significant, overestimation of GFR when the original MDRD equation is used. This positive bias was reduced (ID-MS 6.7 to 0.4%; enzymatic 8.8 to 3.4%; compensated kinetic Jaffe 13.7 to 7.1%) when GFRs were calculated using the ID-MS-traceable MDRD equation. CONCLUSIONS: Compensated assays that account for non-creatinine chromogen interference produce significantly higher estimates of GFR when using the original MDRD equation. Use of the ID-MS-traceable MDRD equation ameliorates this effect. There is good agreement between estimated GFR derived from the original MDRD equation using Beckman Astra CX3 data and estimated GFR derived from the new ID-MS-traceable MDRD equation using a local ID-MS creatinine assay. This suggests that the ID-MS-traceable MDRD equation may be reliably used with both ID-MS and true ID-MS-traceable creatinine assays without the requirement for standardization to the MDRD laboratory. KW - gfr AU - Vickery, S AU - Stevens, PE AU - Dalton, RN AU - van Lente, F AU - Lamb, EJ PY - 2006/09// UR - http://dx.doi.org/10.1093/ndt/gfl249 ER -