HIV 1,2 Ag/Ab Combo p24-antigen Signal/Cutoff

A combined HIV antigen and antibody screen reported against a signal cutoff.

Last reviewedJune 16, 2026

Serum

sample type

~5 mL

blood needed

~7 days

results in app

Any time of day

best timing

INCLUDED WITH ANIVA

199 € / year

0.55 € a day

Get Started

100+ biomarkers. Cheaper than a comparable test at your doctor. Guaranteed, or we match the price.

German PKV insurance usually reimburses.

On this page

Why test Reference ranges What you'll learn What affects it How testing works Sources FAQ

In short

This is the p24 antigen part of a combined HIV test, reported as a Signal-to-Cutoff (S/Co) index. p24 is a protein from the core of the HIV virus that appears in the blood very early after infection, often before antibodies can be measured.

The S/Co value compares the signal from your sample against the test's cutoff line. A value below 1.0 is non-reactive, and a value at or above 1.0 is reactive.

Inflammation & Immune

Reviewed against DGKL reference practice.

Why test this?

The p24 antigen helps catch HIV earlier than antibody testing alone, narrowing the window between exposure and a detectable result. This matters because early infection is when the virus level is high and treatment is most valuable.

A non-reactive S/Co is reassuring for the period the test covers. A reactive S/Co points to possible early infection and must be confirmed with further testing before any diagnosis.

What is a normal result?

Aniva reads your result against research-backed ranges, not just the lab's wide normal. The reference shown below is specific to this biomarker.

This component is reported as a Signal-to-Cutoff (S/Co) index.

S/Co value	Interpretation
Less than 1.0	Non-reactive (negative)
1.0 or above	Reactive, needs confirmation

The cutoff is defined by the assay and may vary by laboratory. A reactive result is not a diagnosis on its own.

Ranges are guidance and vary by lab and assay, aligned with DGKL practice. Always read your result against your own lab's reference interval.

What insights will this test give you?

You see where your p24 signal sits relative to the cutoff. An S/Co below 1.0 is non-reactive. An S/Co at or above 1.0 is reactive and needs confirmatory testing. The number itself is not a viral load and is not a diagnosis.

What can affect this result?

What can skew the result

p24 antigen can fall as antibodies rise later in infection, so a single value reflects one moment in time. Very recent exposure can still be missed. Rare false-reactive results are possible, which is why confirmation is required. Fasting and time of day do not affect the result.

Best interpreted with

Read with the HIV antibody result from the same combo test and with confirmatory testing if the screen is reactive.

How is this tested?

Sample

Serum

Blood needed

~5 mL

Method

Immunoassay

Best timing

Any time of day

Sources. The evidence behind this

WHO: HIV and AIDS

CDC: HIV Testing

Robert Koch-Institut: HIV/AIDS

Common questions

Which Aniva panels include this marker?

STI Screening

These tests screen for the most common sexually transmitted infections.