What does the Hoesch screening test evaluate?

The Hoesch screening test specifically evaluates the presence of urinary porphobilinogen. This test is critical in the diagnosis of porphyrias, a group of disorders resulting from enzyme deficiencies in the heme biosynthetic pathway. Elevated levels of porphobilinogen in urine are indicative of certain types of porphyria, particularly acute intermittent porphyria.

This test is particularly useful because porphobilinogen is a more stable metabolite than other porphyrins and can be detected in urine, making it a valuable tool for identifying these metabolic disorders. The presence of porphobilinogen in the urine can lead to symptoms such as abdominal pain, neuropsychiatric symptoms, and photosensitivity, which are characteristic of porphyric crises.

Other options like bilirubin levels, nitrite presence, and leukocyte counts pertain to different aspects of urine analysis. Bilirubin levels are assessed to evaluate liver function or biliary obstruction, nitrite presence is a test for urinary tract infections, and leukocyte counts are used to indicate inflammation or infection in the urinary tract. However, none of these tests specifically screen for porphobilinogen, which is the focus of the Hoesch screening test.