Medical Moment Tuesday

Medical Moment-

My doctor diagnosed me with porphyria, but the porphyria expert said I did not have it. Why would this happen, and should I be retested?

Such a situation needs to be dealt with on an individual basis. Whether further testing is recommended depends on how the patient was initially diagnosed and how the porphyria expert made the decision that porphyria is not the diagnosis. The results of biochemical testing are sometimes interpreted incorrectly by a physician who is not an expert in porphyria. Review of the results of the biochemical testing by a porphyria expert may determine that the results are not consistent with what is typically seen in a patient with porphyria during an attack. The results of DNA analysis may also contribute to the porphyria expert saying that it is unlikely that the patient has porphyria. DNA analysis, although considered to be the “gold standard” for diagnosis, is not perfect in that the patient may have a mutation in a part of the porphyria gene that is not analyzed by routine testing or the patient has a mutation in a porphyria gene that was not analyzed. If a diagnosis of porphyria is still suspect, then it is recommended that the patient undergo additional biochemical testing at the time of an acute attack. Additionally, further testing may include DNA analysis for other acute porphyrias (if only one or two were tested).

 

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