TN 7 (08-22)

DI 24555.005 Using Laboratory Testing to Evaluate Genitourinary Impairments

A. Background

This section provides information about laboratory testing we use to evaluate genitourinary disorders under the criteria in listings 6.05, 106.05, and 6.06. We can also use laboratory test results when evaluating residual functional capacity.

For more information about evaluating chronic kidney disease, see DI 34001.020 and DI 34005.106.

B. Glomerular filtration rate (GFR) and estimated glomerular filtration rate (eGFR)

GFR is the rate at which the kidneys filter waste and extra fluid from the blood, measured in milliliters per minute. Although it is possible to measure the GFR directly, the process is intrusive and time-consuming. Therefore, most treating sources use an eGFR as the measure of kidney function. We consider eGFR results under the criteria in listings 6.05 and 106.05.

1. Equations for calculating eGFR

Laboratories may use different equations to calculate eGFR. Equations consider serum creatinine levels and some or all of the following factors: age, gender, body size, and race. Race is not a factor in eGFR equations for children. We consider all eGFR equations when we evaluate chronic kidney disease under listings 6.05 and 106.05.

Examples of eGFR equations include:

  • The Modification of Diet in Renal Disease (MDRD) equation (used for adults age 18 or older),

  • The Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation (used for adults age 18 or older), or

  • The Bedside Schwartz equation (for children under age 18).

NOTE: Do not calculate the eGFR if the laboratory did not provide it.

2. Laboratory reporting of eGFR

Laboratories may report different eGFR values based on a person's race. For example, the report may contain:

  • One eGFR value for the person’s identified race,

  • One eGFR value for African Americans and a second eGFR value for other races, or

  • One eGFR value for other races and an instruction to multiply this value by an adjustment factor (usually recorded next to the eGFR value in the laboratory report) if the person is African American.

On September 23, 2021, the National Kidney Foundation (NKF) and American Society of Nephrology (ASN), published a report recommending that laboratories should not include race in eGFR calculation and reporting.[1] In response to this recommendation, we will use the unadjusted eGFR value for all persons, regardless of race. Some examples of how laboratories may report the unadjusted eGFR value include “eGFR,” “eGFR Non-African American,” “eGFR Non-Black,” or “eGFR Caucasian.”

If the person is African American, and the laboratory reports:

  • An unadjusted eGFR value and an eGFR value for African Americans, use the unadjusted eGFR value.

  • An unadjusted eGFR value and an instruction to multiply this value by an adjustment factor if the person is African American, use the unadjusted eGFR value. Do not multiply the eGFR value by the adjustment factor.

Contact the medical source to obtain the unadjusted eGFR if the person is African American and the laboratory reports:

  • One eGFR value for African Americans, or

  • One eGFR value and it is unclear whether the eGFR value was adjusted for race,

AND

  • All of the following conditions apply:

    • There are no other laboratory findings in the medical evidence that satisfy the criteria in listing 6.05A,

      and

    • The person has at least one of the additional impairments required in listing 6.05B, and

    • Using the unadjusted eGFR value may change the determination of the claim.

NOTE: Many laboratories currently report the unadjusted eGFR value and more laboratories will do so as they implement NKF and ASN’s recommendation. We only need to contact the medical source if all the conditions listed above apply. To expedite development, we may use the telephone to obtain the unadjusted eGFR. For more information on obtaining medical evidence by telephone, see DI 22505.030.

C. Urine total-protein-to-creatinine ratio (UPCR)

The UPCR reflects the relationship between the urine total protein to the urine total creatinine. We consider the UPCR under the criteria in listing 6.06.

1. Laboratory reporting of UPCR

If a laboratory provides both the urine total protein and urine total creatinine values, it will usually report them using the same units of measurement. In this instance, the laboratory will normally include the UPCR in the report. We accept UPCR values calculated from random (spot) urine samples or timed collections (including 24-hour collections).

2. Calculating UPCR

If the laboratory does not provide the UPCR, we may calculate the ratio if all of the following apply to the urine total protein and urine total creatinine values:

  • Reported in the same units of measurement,

  • Recorded on the same laboratory report, and

  • Performed on the same day.

To calculate the UPCR, divide the urine total protein by the urine total creatinine.

NOTE: Use laboratory values from urine tests to calculate the UPCR. Laboratories sometimes report serum creatinine values instead of urine creatinine. Do not use serum creatinine laboratory values to calculate the UPCR.

D. Urine albumin-to-creatinine ratio (ACR)

The ACR reflects the relationship between the urine albumin to the urine creatinine. Albumin is one of the proteins measured in the UPCR. We may use the ACR to evaluate medical equivalence under listing 6.06. For purposes of medical equivalence, an ACR value that is equal to or greater than 3.5 is of equal medical significance to a UPCR of 3.5 or greater. We accept ACR values calculated from random (spot) urine samples or timed collections (including 24-hour collections).

E. References


Footnotes:

[1]

See Delgado, C. et al. A Unifying Approach for GFR Estimation: Recommendations of the NKF-ASN Task Force on Reassessing the Inclusion of Race in Diagnosing

Kidney Disease, American Journal of Kidney Diseases, Sep. 79(2), 268-288 (2021).


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DI 24555.005 - Using Laboratory Testing to Evaluate Genitourinary Impairments - 08/23/2022
Batch run: 08/23/2022
Rev:08/23/2022