What can cause thick turbidity in refrigerated urine specimens?

Thick turbidity in refrigerated urine specimens is often caused by the presence of amorphous deposits. These deposits are non-crystalline substances such as urates or phosphates that precipitate out of urine when it is cooled. This occurs because the solubility of certain salts decreases at lower temperatures, leading to the formation of these deposits, which contribute to the cloudy or turbid appearance of the urine when examined after refrigeration.

In contrast, pathological conditions may lead to turbidity due to the presence of cells, bacteria, or other components, but they might not specifically result in a thick turbidity after refrigeration. Similarly, normal hydration tends to produce clearer urine, and high specific gravity indicates concentration but does not necessarily lead to turbidity in the same way as amorphous deposits. Therefore, the correct answer identifies the specific physical change due to temperature alteration in the urine without the influence of pathological processes or hydration status.