This term is actually contradictory. It confirms that the person does indeed have HIV, contracted by blood transfusion or sexual contact with a sambo/coon. This disease leads to BLAIDS, which is black AIDS. It not only kills you, but steals your money and property as it does so.
Becky: I just got tested and I'm HIV Niggative.
Stacy: OMG, you must have caught it when you was wog stretched by Ten inch Tyrone.
Me: Would you like some watermelon with your chicken?
Africanishaniqua: *shakes head in niggation* NUH-UH
Me: OK, you could've just said no. There's no need for niggations in my shop.