Pediatric Environmental Health Center | Lead

EP level stands for erythrocyte protoporphyrin. Another term that is commonly used is zinc protoporphyrin or ZPP. In the past, this test was also known as a free erythrocyte protoporphyrin (FEP).

EP is a chemical that everyone makes in the process of creating new red blood cells (red blood cells carry oxygen in the blood). In children with high lead levels, EP becomes elevated because lead interferes with the creation of red blood cells. Screening by measuring this chemical in the blood (erythrocyte protoporphyrin, or EP) is done every time your child has a lead level drawn.

The EP helps to determine whether the lead in the child's system is having any type of effect on the body that we can measure. EP is one of the only ways to look for an effect of lead on the child. By looking at EP we can get a better idea of how much lead is in the body. Another way to think about EP is this: because EP is made in the body's tissues, if EP is elevated, it suggests that other body tissues (such as the kidney or brain) are also being affected by the lead.

The EP can sometimes also be used to determine for how long the child was exposed to lead. It can also determine whether the child is still being exposed to lead; when children have another exposure to lead, the EP will rise. Finally, the EP helps the doctor to manage the child's lead poisoning; as the lead poisoning is treated (for example, with chelation), the EP falls to the normal range.

The normal range for ZPP is zero to 35.

Iron deficiency can also raise your child's EP. So, if your child is anemic he/she may have an elevated EP from anemia and not from lead poisoning. Still, the EP is very useful for a few reasons. First, even though iron deficiency and lead poisoning both raise EP, you can usually tell which of these is responsible. Second, if an EP is elevated because the child has iron deficiency, the doctor can immediately start giving iron supplements to correct the deficiency.

Penicillamine is a drug that binds with lead in the body and increases its removal in the urine. Its brand name is Cuprimine. Penicillamine will get the lead out of the body, but it sometimes takes several months to do so.

Penicillamine is available as a capsule or tablet. The capsule can be opened and sprinkled on food, or mixed into a small amount of liquid. The tablet may be crushed with a spoon. Capsules are available in 125 mg or 250 mg strength. Tablets are 250 mg, but they are scored so they can be broken in half or quartered.

It may be given with fruit juices, applesauce, chocolate syrup, Zarex (fruit juice concentrate), jelly, or non-dairy whipped cream. It should be given on an empty stomach (30 minutes before or two hours after meals). A few children however, may complain of an upset stomach when it is given with food and they may need some crackers or a small snack.

It is very important that your child receives all of the doses of penicillamine that the doctor has ordered. Because of the potential adverse effects of penicillamine, it is also important that your child returns to the Lead Clinic for all of his/her scheduled visits. When you child begins penicillamine, it is essential for us to see him/her in the Lead Clinic two weeks after starting treatment. After two weeks on the medication, if all is going well, we can space the visits out to once a month.

Your child may need to take penicillamine for as long as three to four months.

Iron treatment should not be given at the same time as penicillamine, and penicillamine should not be given with milk or milk products. You can give penicillamine two hours before or two hours after any iron or calcium product.

Your doctor will have discussed the possible but unlikely side effects of penicillamine with you. Pharmacy information and medication labelling give side effects for penicillamine when it is used in adults for other illnesses. The risk of side effects when penicillamine is given to children is extremely low and completely different than the risks for the adult.

These side effects include allergy to the drug (5 to 7 percent risk), which may cause a skin rash, a decrease in the number of white blood cells and/or platelets (risk is less than 1 percent). The rash of penicillamine consists of red, raised bumps on the face and/or trunk. These side effects will go away when the medication is stopped.

A strong medication odor appears in the urine when children are taking penicillamine; this is to be expected and it is not a problem. Since we are looking for any changes in your child's blood and urine, we will ask for a blood test and urine sample at each visit.

DMSA, also known as Chemet and Succimer, is a drug that binds with the lead in the body and increases its removal in the urine.

DMSA comes in capsules only. The capsule can be opened and sprinkled on food if your child is unable to swallow pills.

The medicine has a bad smell and taste. It will be better tolerated by your child if it is mixed with something sweet tasting such as chocolate syrup, ice cream, pudding, or jellies. The capsule can be mixed with food five to 10 minutes before administering so that some of the smell will evaporate.

DMSA is dosed according to your child's weight and is given over a specified course of time by your doctor. It is very important that your child receives all of the doses of DMSA that the doctor has ordered or the medicine will not work as it should. It is also important that your child returns to the Lead Clinic for all his/her scheduled visits, so that we can monitor him/her for any possible side effects. Your child may need a second or even third course of DMSA in a few weeks.

DMSA may cause some temporary elevations in your child's liver enzymes. We will draw blood work at each clinic visit both to monitor his/her lead levels and to look for any possible adverse effects. DMSA may also cause a skin rash, however, this is rare.

If your child develops a rash while taking DMSA or if you have other questions or concerns please call the Lead Clinic on Monday, Wednesday, or Friday to speak with the nurse. You can also page your Lead Clinic doctor or the toxicology fellow on call.

Either person can be reached by calling the page operator at 617-355-6369. Nora Llach, RN, MPH, Boston Children's Hospital