Minute quantities of blood in feces, urine, and gastric fluid, detectable only by microscopic examination or chemical test.
Blood in such minute quantities that it can be seen only by microscopic examination.
Very small quantities of blood in the faeces, which can only be detected by tests.
A very small or hidden amount of blood, not observable and usually detected only by chemical tests or microscopic analysis (e.g., occult blood in the stool of someone with an intestinal disorder).
Hidden blood in stool that is not visible to the unaided eye.
Blood that is present in such small quantities that it is not apparent to the eye. Blood may be present in feces but of such color and consistency as to be unnoticed by the patient. Occult blood is usually detected only by chemical tests or by microscopic or spectroscopic examination.
Microscopic hematuria refers to the presence of blood in the urine that is not visible to the naked eye.
Blood that is not visible to the unaided eye.