Is a simple, convenient method for collecting duodenal contents. ▪ The terminal end of the yarn should be yellow-green, indicating that it was in the duodenum. ▪ After 4 hours, the yarn is retrieved and the mucoidal material clinging to the yarn is examined for parasites including S. stercoralis, G. lamblia, Cryptosporidium spp., microsporidia, and the eggs of Clonorchis sinensis ▪ If the specimen cannot be completely examined within 1 hr after removal of the yarn, the material should be preserved in 5% to 10% formalin or PVA-mucus smears should be prepared.