Intermediates of the heme biosynthetic pathway, chemical alterations that occur when they accumulate, routes of excretion, and samples collected for their measurement

Pathway intermediate*	Chemically altered forms^¶	Primary routes of excretion	Samples for measurement^Δ
δ-Aminolevulinic acid	None	Kidney	Urine, plasma
Porphobilinogen	Porphobilin; uroporphyrin	Kidney	Urine, plasma
Uroporphyrinogen (octacarboxyl porphyrin) I & III	Uroporphyrin I & III	Kidney	Urine, plasma
Heptacarboxyl porphyrinogen I & III	Heptacarboxyl porphyrin I & III	Kidney	Urine, plasma
Hexacarboxyl porphyrinogen I & III	Heptacarboxyl porphyrin I & III	Kidney	Urine, plasma
Pentacarboxyl porphyrinogen I & III	Pentacarboxyl porphyrin I & III	Kidney	Urine, plasma
Coproporphyrinogen (tetracarboxyl-porphyrinogen) I & III	Coproporphyrin I & III	Kidney and liver	Urine, feces, plasma
Harderoporphyrinogen (tricarboxyl-porphyrinogen)	Harderoporphyrin	Liver	Feces, erythrocytes
Protoporphyrinogen IX	Protoporphyrin IX	Liver	Feces, plasma
Protoporphyrin IX	None	Liver	Feces, erythrocytes

Refer to UpToDate for an overview of the approach to a patient with suspected porphyria and the details of evaluations for specific porphyrias.

δ: delta.
* All intermediates are colorless and nonfluorescent, with the exception of protoporphyrin, which is reddish and fluorescent.
¶ The autooxidized porphyrins are reddish and fluorescent; porphobilin is brownish.
Δ Urine and fecal porphyrins are fractionated if the total is increased; plasma porphyrins may be fractionated, but for differential diagnosis it is preferred to determine the fluorescence peak at neutral pH.

Provided by Karl Anderson, MD, FACP.

Graphic 75386 Version 7.0

خرید پکیج

Intermediates of the heme biosynthetic pathway, chemical alterations that occur when they accumulate, routes of excretion, and samples collected for their measurement