Glomerular Filtration Rate 2

Illustrates Domains

Illustrates Variables

LBTESTCD
LBTEST
LBMETHOD
LBANMETH

Content

In this example, blood was collected from a 45-year-old, male, Caucasian subject, and creatinine and cystatin C levels were measured.

There are two ways to calibrate creatinine measurement: traditional vs. IDMS (isotope dilution mass spectrometry) traceable. IDMS traceability indicates that the creatinine method used (such as enzymatic or Jaffe method) has calibration traceable to an IDMS reference measurement procedure, and therefore a validated, IDMS-traceable equation should be used and noted for the eGFR calculation. In the example below, the serum creatinine test was performed via the enzymatic-based creatinine assay using a calibration traceable to IDMS. Because of this, the version of the 4-variable MDRD equation that is IDMS-traceable (as opposed to the version of the equation that uses "traditional" calibration type, which changes the coefficient from 175 to 186, LB Rows 3 and 6) was used to calculate the subject’s eGFR.

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Row 1:	Shows the result of serum creatinine measurement from the subject.
Row 2:	Shows the result of serum cystatin C measurement from the same subject on the same visit.
Row 3:	Shows an example of an estimated glomerular filtration rate (eGFR) calculated using the serum creatinine result in Row 1 and the 4-variable MDRD equation[5], which is also IDMS-traceable. The name of the eGFR equation is represented by the LBANMETH variable; in this instance, the eGFR equation used is the US version of the IDMS-4-varaible MDRD formula. Depending on the ethnic background of the population under study, the coefficients and components in the eGFR equation may vary, this is the reason why the text "US VERSION" is included as part of the equation name.
Row 4:	Shows the result of serum creatinine measurement from the same subject at Week 2 visit.
Row 5:	Shows the result of serum cystatin C measurement from the same subject at Week 2 visit.
Row 6:	Shows eGFR at the Week 2 visit, calculated using the serum creatinine result in Row 4 and the 4-variable MDRD equation, which is also IDMS traceable.

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Row	STUDYID	DOMAIN	USUBJID	LBSEQ	LBREFID	LBTESTCD	LBTEST	LBCAT	LBORRES	LBORRESU	LBORNRLO	LBORNRHI	LBSTRESC	LBSTRESN	LBSTRESU	LBSTNRLO	LBSTNRHI	LBNRIND	LBSPEC	LBMETHOD	LBANMETH	VISIT	VISITNUM	LBDTC
1	ArBit 01	LB	AB01-001	1	A12567	CREAT	Creatinine	CHEMISTRY	1.5	mg/dL	0.7	1.3	1.5	1.5	mg/dL	0.7	1.3	HIGH	SERUM	ENZYMATIC COLORIMETRY		Week 1	1	1999-06-19
2	ArBit 01	LB	AB01-001	2	A12567	CYSTATC	Cystatin C	CHEMISTRY	1.4	mg/L	0.52	0.9	1.4	1.4	mg/L	0.52	0.9	HIGH	SERUM	PARTICLE-ENHANCED TURBIDIMETRIC IMMUNOASSAY		Week 1	1	1999-06-19
3	ArBit 01	LB	AB01-001	3	A12567	GFRE	Glomerular Filtration Rate, Estimated	CHEMISTRY	51	mL/min/1.73m2	90	120	51	51	mL/min/1.73m2	90	120	LOW		CALCULATION	IDMS-4-VARIABLE MDRD EQUATION-US VERSION	Week 1	1	1999-06-19
4	ArBit 01	LB	AB01-001	4	A12567	CREAT	Creatinine	CHEMISTRY	1.6	mg/dL	0.7	1.3	1.6	1.6	mg/dL	0.7	1.3	HIGH	SERUM	ENZYMATIC COLORIMETRY		Week 2	2	1999-06-26
5	ArBit 01	LB	AB01-001	5	A12567	CYSTATC	Cystatin C	CHEMISTRY	1.37	mg/L	0.52	0.9	1.37	1.37	mg/L	0.52	0.9	HIGH	SERUM	PARTICLE-ENHANCED TURBIDIMETRIC IMMUNOASSAY		Week 2	2	1999-06-26
6	ArBit 01	LB	AB01-001	6	A12567	GFRE	Glomerular Filtration Rate, Estimated	CHEMISTRY	47	mL/min/1.73m2	90	120	47	47	mL/min/1.73m2	90	120	LOW		CALCULATION	IDMS-4-VARIABLE MDRD EQUATION-US VERSION	Week 2	2	1999-06-26

The following example shows results from tests on blood, which was collected from a 69-year-old, male, African American subject. The creatinine level was measured, and the estimated glomerular filtration rate was calculated using the CKD-EPI equation, which incorporates creatinine value only.

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Row 1:	Shows the result of serum creatinine measurement from an African American male subject.
Row 2:	Shows eGFR calculated using the serum creatinine result in Row 1 and the CKD-EPI (Creatinine) equation[4]. The name of the eGFR equation is represented by the LBANMETH variable; in this instance, the eGFR equation used is the US version of the CKD-EPI (Creatinine) formula. Depending on the ethnic background of the population under study, the coefficients and components in the eGFR equation may vary, this is the reason why the phrase "US VERSION" is included as part of the equation name

Row 1:

Shows the result of serum creatinine measurement from an African American male subject.

Row 2:

Shows eGFR calculated using the serum creatinine result in Row 1 and the CKD-EPI (Creatinine) equation[4]. The name of the eGFR equation is represented by the LBANMETH variable; in this instance, the eGFR equation used is the US version of the CKD-EPI (Creatinine) formula. Depending on the ethnic background of the population under study, the coefficients and components in the eGFR equation may vary, this is the reason why the phrase "US VERSION" is included as part of the equation name

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Row	STUDYID	DOMAIN	USUBJID	LBSEQ	LBREFID	LBTESTCD	LBTEST	LBCAT	LBORRES	LBORRESU	LBORNRLO	LBORNRHI	LBSTRESC	LBSTRESN	LBSTRESU	LBSTNRLO	LBSTNRHI	LBNRIND	LBSPEC	LBMETHOD	LBANMETH	VISIT	VISITNUM	LBDTC
1	ArBit 01	LB	AB01-022	1	A12522	CREAT	Creatinine	CHEMISTRY	1.8	mg/dL	0.7	1.3	1.8	1.8	mg/dL	0.7	1.3	HIGH	SERUM	ENZYMATIC COLORIMETRY		Week 1	1	1999-04-02
2	ArBit 01	LB	AB01-022	2	A12522	GFRE	Glomerular Filtration Rate, Estimated	CHEMISTRY	44	mL/min/1.73m2	90	120	44	44	mL/min/1.73m2	90	120	LOW		CALCULATION	CKD-EPI (CREATININE) EQUATION-US VERSION	Week 1	1	1999-04-02

The estimated glomerular filtration rate (eGFR) can be calculated using various published, standard equations[2][4][5]. eGFR equations are also available for some populations that were not well represented in the cohorts used to develop the original equations, for instance, for people of Japanese ancestry[9][10]. It is important to note that CDISC does not mandate any one eGFR equation to use. However, please consider eGFR equations that are appropriate for the ethnic background of the population under study.