LABORATORY UPDATE:  HIV real-time PCR assay

                              
September 3, 2010

Bendiner and Schlesinger Inc. is proud to announce the availability of the COBAS® AmpliPrep / COBAS® TaqMan® HIV-1 real-time PCR assay. The assay uses nucleic acid amplification for the quantitation of Human Immunodeficiency Virus Type 1 (HIV-1) RNA in human plasma. Bendiner and Schlesinger Inc. is offering this test based on performance, comparability of patients results over time, and the ability of the test to capture genetically diverse HIV-1variants.


Test performance

Bendiner and Schlesinger Inc.’s goal is to provide standard of care performance to our clinicians

  • The COBAS® AmpliPrep / COBAS® TaqMan® HIV-1 Test utilizes Roche’s proven real-time PCR technology that has been available to clinicians for more than 3-years and has been retained by laboratories throughout the world. 

As you transition to Roche real-time PCR testing it is important to understand the test standardization and the analytical performance characteristics of the assay.

Test Parameter COBAS® AmpliPrep / COBAS® TaqMan® HIV-1 Test
Limit of Detection 48 cp/mL (copies/mL)
Reportable and Linear Range 48-10,000,000 cp/mL
Reportable Units copies/mL (also log base 10)
Subtype Inclusivity roup M, Subtype A-H
Sample Type EDTA Plasma (EDTA?)
Standardization WHO 1st International Standard

Improvements in testing technologies have lead to minor differences in viral load test results. 

 

Comparability of patient result over time

Recognizing that viral load monitoring requires result comparability over time, Bendiner and Schlesinger Inc. focused on adopting a real-time PCR test that would minimize disruption in viral load trending and that would optimize reproducibility of test results.

  • Our evaluations concluded that the Roche real-time PCR test was produced with the platform that offers minimal manual human interventions minimizing the likelihood of human error and increasing reproducibility of test results.

 

Quantifying the HIV virus

The HIV virus is prone to genomic mutations that are both viral and drug- induced. Natural viral polymorphism combined with drugs that can apply a selective pressure may cause new HIV variants to emerge. A key selection criteria was to ensure the test is optimally designed to minimize the number of rare variants that may go undetected or underquantitated.

  • The Roche test amplifies the gag region which is not subject to antiretroviral drug pressures.*
  • The Roche real-time PCR test has been designed with a unique phased-matched thermal cycling approach to provide mismatch tolerance.
  • Roche, the manufacturer of the test, has provided data and is FDA approved for full HIV-1 Group M coverage including the rare non-B subtypes. This data is available in the package insert that can be provided by our local Roche Diagnostics representative or available online at: http://www.mylabonline.com
  • Roche offers a Global Surveillance Program for the purposes of tracking the prevalence of rare and emerging HIV-1 variants. As a part of this program, Roche accepts and analyzes unusual samples from around the world. The information gathered through the program is utilized by Roche to continuously address newly characterized mutations and account for the mutations in new test versions. This new test is Roche’s 7th generation of HIV viral load test.

To order this test, use test code: 5218-HIV-PCR Viral Load-TaqMan

If you have any questions about this new method and our internal validation studies please contact the laboratory directly.

Sincerely,

Shelley Melzer
Director of Operation

*Infectious Disease Study: Human Immunodeficiency Virus. Decision Resources, Inc. Waltham, Massachusetts. July 2009.