Endogenous pigments are characterized as hematogenous and nonhematogenous. Hematogenous pigments originate from blood, and nonhematogenous pigments originate from non-blood, fat or fatlike, and non-fatlike substances. Table 4 displays examples of both hematogenous and nonhematogenous pigments.
Table 4. Examples of Endogenous Pigments.| Endogenous Pigment | Classification | Comments |
| Hemosiderin | Hematogenous | - Hemosiderin is ferric (+3) iron and can be identified in organs such as the liver, spleen, and bone marrow.
- Often demonstrated in the condition known as hemosiderosis, caused by an increase in iron intake.
- Hemosiderosis may be attributed to transfusion, excess dietary iron consumption, or the breakdown of red blood cells.
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| Lipofuscin | Nonhematogenous, fatlike | - One of the most common endogenous pigments found in human tissues.
- A yellowish-brown pigment that is found in increased amounts as cells age.
- Commonly known as "age pigment."
- Nerve, cardiac, and liver cells commonly demonstrate lipofuscin.
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| Bilirubin | Hematogenous | - A bile pigment that is excreted by the hepatocytes of the liver.
- When bilirubin is not excreted by hepatocytes, jaundice or yellowing of the skin can occur.
- Jaundice is characteristic of several liver diseases.
- A commonly known liver disease that causes jaundice in infants is neonatal hyperbilirubinemia, caused by hepatocytes that have underdeveloped smooth endoplasmic reticulum (SER).
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| Copper | Nonhematogenous, non-fatlike | - A unique characteristic of fetal liver tissue is that it will always demonstrate the presence of copper.
- For this reason, fetal liver tissue acts as a good copper tissue control.
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