source studies Blood 67 Feces 11 Liver 10 Spinal cord 8 Heart 5 Cecum 4 Kidney 4 Macrophages 4 Cultured cells 4 Muscle 3 Lung 3 Colon 3 Intestine 2 Fibroblast cells 2 Brain 2 Cells 2 Scalp 1 Small intestine 1 Spleen 1 Stomach 1 Suspended Marine Particulate Matter 1 Thyroid 1 Tumor cells 1 Tumor tissue 1 Unspecified 1 Vaginal epithelium 1 Algae 1 Worms 1 Amniotic fluid 1 Bacterial cells 1