Denatured pearl protein vesicles, also known as hemoglobin inclusion bodies, are actually denatured hemoglobin particles, usually attached to cell membranes, and occur most often in sensitive individuals after taking medications or being exposed to chemicals, which can lead to Hb denaturation; this inclusion body can also be seen in certain patients with unstable Hb, and is therefore definitive in glucose-6-phosphate dehydrogenase deficiency as well as in unstable Hb disease, the stains as blue-black dots.