Serum Creatinine and eGFR

Illustrates Domains

Illustrates Variables

LBORRES
LBORRESU
LBLOINC
LBSPEC
LBMETHOD
LBANMETH
LBLOBXFL

Content

This example shows serum creatinine measurements. There are 2 ways to calibrate creatinine measurements: traditional or isotope dilution mass spectrometry (IDMS)-traceable. IDMS traceability means that the creatinine method used (e.g., enzymatic, Jaffe method) has calibration traceable to an IDMS reference measurement procedure. In this example, the serum creatinine test was performed via the enzymatic-based creatinine assay using a calibration traceable to IDMS and the US version of the 4-variable modification of diet in renal disease (MDRD) study equation[4] for the eGFR. Depending on the ethnic background of the population under study, the coefficients and components in the eGFR equation may vary; this is why the text "US VERSION" is included as part of the equation name. The LOINC values were provided by the reporting laboratory and example values are included.

Serum creatinine is usually measured many times over the course of a clinical trial to assess AKI severity. Here the serum creatinine measurements and estimated GFR are shown for a few days at the beginning of the trial and then again at day 90, with a confirmatory measurement at 14 days after the 90-day visit. There may be other measures in between these time points; however, for simplicity only a few are shown. The endpoint for this example is a greater than or equal to 25% decrease in eGFR at the day 90 visit. The decrease needs to be confirmed at a subsequent specified time point (e.g., 14 days). These data were calculated by the lab

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Row 1:	Shows the baseline result of serum creatinine measurement from the subject.
Row 2:	Shows an example of eGFR calculated using the serum creatinine result in row 1 and the 4-variable MDRD equation, which is also IDMS-traceable. The name of the eGFR equation is represented by the LBANMETH variable.
Rows 3-4:	Show the results of serum creatinine measurement from the same subject on days 2 and 3.
Row 5:	Shows the result of serum creatinine measurement from the subject at the day 90 visit.
Row 6:	Shows eGFR at the day 90 visit, calculated using the serum creatinine result in row 5 and the 4-variable MDRD equation, which is also IDMS-traceable.
Rows 7-8:	Show serum creatinine and eGFR results from a confirmatory visit 14 days after day 90.

lb.xpt

Row	STUDYID	DOMAIN	USUBJID	LBSEQ	LBREFID	LBTESTCD	LBTEST	LBCAT	LBORRES	LBORRESU	LBORNRLO	LBORNRHI	LBSTRESC	LBSTRESN	LBSTRESU	LBSTNRLO	LBSTNRHI	LBNRIND	LBLOINC	LBSPEC	LBMETHOD	LBANMETH	LBLOBXFL	VISITNUM	VISIT	LBDTC
1	XYZ-001	LB	XYZ-001-003	1	A12567	CREAT	Creatinine	CHEMISTRY	0.8	mg/dL	0.7	1.3	0.8	0.8	mg/dL	0.7	1.3	NORMAL	2160-0	SERUM	ENZYMATIC COLORIMETRY		Y	1	BASELINE	2010- 07-11
2	XYZ-001	LB	XYZ-001-003	2	A12567	GFRE	Glomerular Filtration Rate, Estimated	CHEMISTRY	105	mL/min/1.73m2	90	120	105	105	mL/min/1.73m2	90	120	NORMAL	77147-7		CALCULATION	IDMS-4-VARIABLE MDRD EQUATION-US VERSION	Y	1	BASELINE	2010- 07-11
3	XYZ-001	LB	XYZ-001-003	3	A12768	CREAT	Creatinine	CHEMISTRY	1.4	mg/dL	0.7	1.3	1.4	1.4	mg/dL	0.7	1.3	HIGH	2160-0	SERUM	ENZYMATIC COLORIMETRY			2	DAY 2	2010- 07-12
4	XYZ-001	LB	XYZ-001-003	4	A12934	CREAT	Creatinine	CHEMISTRY	1.3	mg/dL	0.7	1.3	1.3	1.3	mg/dL	0.7	1.3	NORMAL	2160-0	SERUM	ENZYMATIC COLORIMETRY			3	DAY 3	2010- 07-13
5	XYZ-001	LB	XYZ-001-003	5	A18234	CREAT	Creatinine	CHEMISTRY	1.7	mg/dL	0.7	1.3	1.7	1.7	mg/dL	0.7	1.3	HIGH	2160-0	SERUM	ENZYMATIC COLORIMETRY			30	DAY 90	2010-10-11
6	XYZ-001	LB	XYZ-001-003	6	A18234	GFRE	Glomerular Filtration Rate, Estimated	CHEMISTRY	51	mL/min/1.73m2	90	120	51	51	mL/min/1.73m2	90	120	LOW	77147-7		CALCULATION	IDMS-4-VARIABLE MDRD EQUATION-US VERSION		30	DAY 90	2010-10-11
7	XYZ-001	LB	XYZ-001-003	7	A22445	CREAT	Creatinine	CHEMISTRY	1.8	mg/dL	0.7	1.3	1.8	1.8	mg/dL	0.7	1.3	HIGH	2160-0	SERUM	ENZYMATIC COLORIMETRY			99	CONFIRMATION	2010-10-25
8	XYZ-001	LB	XYZ-001-003	8	A22445	GFRE	Glomerular Filtration Rate, Estimated	CHEMISTRY	47	mL/min/1.73m2	90	120	47	47	mL/min/1.73m2	90	120	LOW	77147-7		CALCULATION	IDMS-4-VARIABLE MDRD EQUATION-US VERSION		99	CONFIRMATION	2010-10-25