Fibrin thread casts
These casts are hyaline casts embedding, within their matrix, fibrin threads. These threads originate from the passage in the urinary space, of the coagulation proteins (fibrinogen and others). Once in urine, the fibrinogen coagulates and forms fibrin threads. These casts are strongly indicative of glomerulonephritis.Myeloma casts
The typical myeloma casts are described as rather waxy matrix casts coated with macrophages and tubular cells. These casts are thought to originate from the precipitation of light chains at their acid isoelectric point (4,5- 5,0). Some think that these are not true casts but an inflammatory response to a light chain precipitate. It is not sure that these casts are specific to myeloma. Unknown casts
Does someone have any idea about this cast? Casts like this one were observed a few times in patients with acute renal failure. Cellular casts, waxy casts, and many tubular cells were also found in all the cases. A description of a similar cast called "Bubble cast" by N. IMAI is given on his site at http://square.umin.ac.jp/uri_sedi/EBUBBLECAST2.html