August 2023: Test Discontinuation – HIV-1 Western Blot (HIV1CO)

Immediate Test Change

Test Discontinuation – HIV-1 Western Blot (HIV1CO)

Effective August 28, 2023.

HIV-1 Western Blot Antibody Confirmation (HIV1CO) has been discontinued by the performing reference laboratory.

As an alternative, Cleveland Clinic Laboratories recommends HIV-1 p24 Ag + HIV-1-2 Ab, with reflex to differentiation (HIV12C) testing.

This test, which is performed in-house, follows the CDC-recommended screening algorithm of reflex to differentiation.

HIV-1 p24 Ag +HIV-1-2 Ab, with reflex to differentiation (HIV12C)

CPT Code

Performing Laboratory
Cleveland Clinic Laboratories

Chemiluminescent microparticle immunoassay (CMIA)

Specimen Type
Serum: Gold Serum Separation Tube
Plasma: Sodium Heparin, Lithium Heparin (Green), or Lavender K2EDTA Tube

1 mL

Stability (after separation from cells)
Ambient: 72 hours
Refrigerated: 7 days
Frozen ≤ -20°C: 14 days

Clinical Information
HIV screening and diagnosis

Reference Range

Additional Information
The screening assay is an antigen-antibody combination; when reactive, an HIV confirmatory assay is automatically added and performed.

The confirmatory assay is FDA-approved and can differentiate HIV-1 from HIV-2, making it an integral part of the testing algorithm.

If a client performs a fourth-generation screen, HIV-1/2 Ab Confirmatory (HIV12M) testing may be ordered following a repeatedly positive screen.