Test Details
Methodology
Multiplex end-point TaqMan Polymerase Chain Reaction (PCR) allelic discrimination
Result Turnaround Time
4 - 7 days
Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary.
Use
This test is used for identification of APOL1 risk variants to aid the diagnosis and management of APOL1-mediated kidney disease (AMKD). AMKD is a rapidly progressive form of proteinuric kidney disease caused by variants of the APOL1 gene and a second hit.1-3
AMKD occurs in people of African ancestry, specifically of sub-Saharan origin, and is characterized by two APOL1 risk variants, proteinuria, rapid progression, early disease onset, lack of symptoms and other factors such as hypertension or a family history of kidney disease.1,2,4-8 Compared with chronic kidney disease (CKD) patients of African ancestry with zero or one APOL1 risk variant, AMKD patients progress to dialysis nine to 12 years earlier and have a higher decline in the estimated glomerular filtration rate (eGFR).2,9 A definitive diagnosis of AMKD requires a genetic test for the presence of two APOL1 risk variants.1,10-12 New guidelines and recommendations support genetic testing to establish the cause of CKD in patients with signs of AMKD.13,14
Through this program, Labcorp will perform testing using the lab-developed APOL1 Genotype Test. Each patient that meets the eligibility criteria will receive one Labcorp APOL1 Genotype Test and will have access to genetic results counseling included in the program at no cost to the patient. No patients, providers, and/or third-party payers (including commercial health plans and government health care programs) will be billed for the APOL1 testing covered under the program. The ordering physician will not receive any fees or other compensation in connection with the Labcorp APOL1 Genotyping Program, such as for specimen collection, handling or data reporting. Patients meeting the above eligibility criteria, as well as their treating health care providers, are not required to order, purchase, prescribe, and/or obtain any other product or service from Vertex Pharmaceuticals, Labcorp or any of their affiliates.
Labcorp and Vertex Pharmaceuticals reserve the right to rescind, revoke or amend the program for any reason without notice. This program is not valid where prohibited by law. This program is subject to change or discontinuation without notice. Additional terms and conditions apply. No identifiable patient or provider data will be shared with Vertex Pharmaceuticals as part of this program.
Special Instructions
This test is sponsored by Vertex and should only be ordered on eligible patients. Eligible patients include those of African ancestry who may self-identify as Black, African American, African or Afro-Caribbean, a diagnosis of chronic kidney disease, no history of kidney transplant, do not have diabetes and must not be currently treated with dialysis. Testing should not be billed to third-party payers. Please direct any questions regarding this test to APOL1Test@labcorp.com.
Limitations
This test was developed and its performance characteristics determined by Labcorp. It has not been cleared or approved by the Food and Drug Administration.
Specimen Requirements
Specimen
Whole blood (EDTA)
Volume
3-5 mL whole blood
Minimum Volume
3 mL (Note: This volume does not allow for repeat testing.)
Container
Lavender-top (EDTA) tube
Collection Instructions
Specimen should arrive in the laboratory within 48 hours of collection. Indicate date and time of collection on the request form.
Stability Requirements
| Temperature | Period |
|---|---|
| Room temperature | 72 hours (stability data provided is a combination from Covance Perimeter Park Development and Labcorp CMBP labs) |
| Refrigerated | 168 hours (stability data provided is a combination from Covance Perimeter Park Development and Labcorp CMBP labs) |
| Frozen | -20°C = 24 months (stability data provided is a combination from Covance Perimeter Park Development and Labcorp CMBP labs) |
Storage Instructions
Ship specimen at room temperature or frozen. If specimen is stored prior to shipment, store refrigerated (2°C to 8°C) or frozen.
Causes for Rejection
Specimen does not meet collection criteria; leaking tube; clotted blood; grossly hemolyzed specimen or otherwise visibly degraded; contamination by another specimen; specimens containing suspicious foreign material
Footnotes
1. Freedman BI, Burke W, Divers J, et al. Diagnosis, Education, and Care of Patients with APOL1-Associated Nephropathy: A Delphi Consensus and Systematic Review. J Am Soc Nephrol. 2021 Jul;32(7):1765-1778. PubMed 33853887
2. Elliott MD, Marasa M, Cocchi E, et al. Clinical and Genetic Characteristics of CKD Patients with High-Risk APOL1 Genotypes. J Am Soc Nephrol. 2023 May 1;34(5):909-919. PubMed 36758113
3. Friedman DJ, Pollak MR. APOL1 and Kidney Disease: From Genetics to Biology. Annu Rev Physiol. 2020 Feb 10;82:323-342. PubMed 31710572
4. Friedman DJ, Pollak MR. Genetics of kidney failure and the evolving story of APOL1. J Clin Invest. 2011 Sep;121(9):3367-3374. PubMed 21881214
5. Thomson R, Genovese G, Canon C, et al. Evolution of the primate trypanolytic factor APOL1. Proc Natl Acad Sci U S A. 2014 May 20;111(20): E2130-E2139. PubMed 24808134
6. Nguyen A, Suen SC, Lin E. APOL1 Genotype, Proteinuria, and the Risk of Kidney Failure: A Secondary Analysis of the AASK (African American Study of Kidney Disease and Hypertension) and CRIC (Chronic Renal Insufficiency Cohort) Studies. Kidney Med. 2022 Nov 1;4(12):100563. PubMed 36479469
7. Kopp JB, Nelson GW, Sampeth K, et al. APOL1 genetic variants in focal segmental glomerulosclerosis and HIV-associated nephropathy. J Am Soc Nephrol. 2011 Nov;22(11):2129-2137. PubMed 21997394
8. Kidney Disease Improving Global Outcomes (KDIGO) 2012 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease. Kidney Int Suppl. 2013;3:1-150. Accessed at https://kdigo.org/wp-content/uploads/2017/02/KDIGO_2012_CKD_GL.pdf.
9. Tzur S, Rosset S, Skorecki K, Wasser WG. APOL1 allelic variants are associated with lower age of dialysis initiation and thereby increased dialysis vintage in African and Hispanic Americans with non-diabetic end-stage kidney disease. Nephrol Dial Transplant. 2012 Apr;27(4):1498-1505. PubMed 22357707
10. Freedman BI, Kopp JB, Sampson MG, Susztak K. APOL1 at 10 years: progress and next steps. Kidney Int. 2021 Jun;99(6):1296-1302. PubMed 33794228
11. Peralta CA, Bibbins-Domingo K, Vittinghoff E, et al. APOL1 Genotype and Race Differences in Incident Albuminuria and Renal Function Decline. J Am Soc Nephrol. 2016 Mar;27(3):887-893. PubMed 26180129
12. Rosenberg AZ, Kopp JB. Focal Segmental Glomerulosclerosis. Clin J Am Soc Nephrol. 2017 Mar 7;12(3):502-517. PubMed 28242845
13. Kidney Disease: Improving Global Outcomes (KDIGO) CKD Work Group. KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease. Kidney Int. 2024 Apr;105(4S):S117-S314. PubMed 38490803
14. Franceschini N, Feldman DL, Berg JS, et al. Advancing Genetic Testing in Kidney Diseases: Report From a National Kidney Foundation Working Group. Am J Kidney Dis. 2024 Dec;84(6):751-766. PubMed 39033956
LOINC® Map
| Order Code | Order Code Name | Order Loinc | Result Code | Result Code Name | UofM | Result LOINC |
|---|---|---|---|---|---|---|
| 407154 | STP APOL1 Genotyping | 104664-8 | 407155 | Result | 104664-8 | |
| 407154 | STP APOL1 Genotyping | 104664-8 | 407161 | Interpretation | 93479-4 | |
| 407154 | STP APOL1 Genotyping | 104664-8 | 407156 | Additional Clinical Info | 55752-0 | |
| 407154 | STP APOL1 Genotyping | 104664-8 | 407163 | Limitations | 62364-5 | |
| 407154 | STP APOL1 Genotyping | 104664-8 | 407157 | Methodology | 49549-9 | |
| 407154 | STP APOL1 Genotyping | 104664-8 | 407158 | References | 75608-0 | |
| 407154 | STP APOL1 Genotyping | 104664-8 | 407159 | Director Review | 72486-4 | |
| Order Code | 407154 | |||||
| Order Code Name | STP APOL1 Genotyping | |||||
| Order Loinc | 104664-8 | |||||
| Result Code | 407155 | |||||
| Result Code Name | Result | |||||
| UofM | ||||||
| Result LOINC | 104664-8 | |||||
| Order Code | 407154 | |||||
| Order Code Name | STP APOL1 Genotyping | |||||
| Order Loinc | 104664-8 | |||||
| Result Code | 407161 | |||||
| Result Code Name | Interpretation | |||||
| UofM | ||||||
| Result LOINC | 93479-4 | |||||
| Order Code | 407154 | |||||
| Order Code Name | STP APOL1 Genotyping | |||||
| Order Loinc | 104664-8 | |||||
| Result Code | 407156 | |||||
| Result Code Name | Additional Clinical Info | |||||
| UofM | ||||||
| Result LOINC | 55752-0 | |||||
| Order Code | 407154 | |||||
| Order Code Name | STP APOL1 Genotyping | |||||
| Order Loinc | 104664-8 | |||||
| Result Code | 407163 | |||||
| Result Code Name | Limitations | |||||
| UofM | ||||||
| Result LOINC | 62364-5 | |||||
| Order Code | 407154 | |||||
| Order Code Name | STP APOL1 Genotyping | |||||
| Order Loinc | 104664-8 | |||||
| Result Code | 407157 | |||||
| Result Code Name | Methodology | |||||
| UofM | ||||||
| Result LOINC | 49549-9 | |||||
| Order Code | 407154 | |||||
| Order Code Name | STP APOL1 Genotyping | |||||
| Order Loinc | 104664-8 | |||||
| Result Code | 407158 | |||||
| Result Code Name | References | |||||
| UofM | ||||||
| Result LOINC | 75608-0 | |||||
| Order Code | 407154 | |||||
| Order Code Name | STP APOL1 Genotyping | |||||
| Order Loinc | 104664-8 | |||||
| Result Code | 407159 | |||||
| Result Code Name | Director Review | |||||
| UofM | ||||||
| Result LOINC | 72486-4 |