<unk>  studies<unk>  is diagnosed through biochemical analysis of blood, urine, and stool. In general, urine estimation of porphobilinogen (PBG) is the first step if acute<unk>  is suspected. As a result of feedback, the decreased production of heme leads to increased production of precursors, PBG being one of the first substances in the<unk>  synthesis pathway. In nearly all cases of acute<unk>  syndromes, urinary PBG is markedly elevated except for the very rare ALA dehydratase deficiency or in patients with symptoms due to hereditary tyrosinemia type I. In cases of mercury- or arsenic poisoning-induced<unk> , other changes in<unk>  profiles appear, most notably elevations of uroporphyrins I & III, coproporphyrins I & III, and pre-coproporphyrin. Repeat testing during an attack and subsequent attacks may be necessary in order to detect a<unk> , as levels may be normal or near-normal between attacks. The urine screening test has been known to fail in the initial stages of a severe, life-threatening attack of acute intermittent<unk> . Up to 90% of the genetic carriers of the more common, dominantly inherited acute hepatic<unk> s (acute intermittent<unk> , hereditary coproporphyria, variegate<unk>  have been noted in DNA tests to be latent for classic symptoms and may require DNA or enzyme testing. The exception to this may be latent post-puberty genetic carriers of hereditary coproporphyria. As most<unk> s are rare conditions, general hospital labs typically do not have the expertise, technology, or staff time to perform<unk>  testing. In general, testing involves sending samples of blood, stool, and urine to a reference laboratory. All samples to detect<unk> s must be handled properly. Samples should be taken during an acute attack; otherwise a false negative result may occur. Samples must be protected from light and either refrigerated or preserved. If all the<unk>  studies are negative, one must consider pseudoporphyria. A careful medication review often will find the cause of pseudoporphyria. Additional tests Further diagnostic tests of affected organs may be required, such as nerve conduction studies for neuropathy or an ultrasound of the liver. Basic biochemical tests may assist in identifying liver disease, hepatocellular carcinoma, and other organ problems.
Porphyria
Alcoholic liver disease
Chalicosis
Lead poisoning
Hepatic porphyria
Pellagra
Albinism
Harderoporphyria