Glofil is the trade name for a substance called 125-I sodium iothalamate. The name was derived from "glomerular filtration," which is a function of the kidneys. The kidneys' major job is to remove toxic waste products from the body. Blood passes through the kidneys and is continuously cleaned and purified. Each kidney contains approximately one million tiny filters called glomeruli. These microscopic filters work by sieving blood, retaining things that the body needs (such as blood cells and protein molecules), and discarding substances that are not needed, such as waste products that accumulate after processing of food. The waste products that are filtered out ultimately make up a large portion of the urine that is excreted from the body.
One way of measuring how well the kidneys work is to give a person a substance that gets filtered out by the glomeruli and excreted in the urine. Glofil is one such substance. It is administered intravenously, and its disappearance from the bloodstream is carefully measured and quantified. Because Glofil contains a tiny amount of radioactivity, the amount of it remaining in the blood can easily be determined by measuring the radioactivity in the body repeatedly over a period of time (usually several hours). The rate at which Glofil disappears allows us to calculate the rate at which glomeruli are filtering it out of the bloodstream, and thus to determine how well the kidneys are working. The amount of radioactivity in a typical dose of Glofil is less than that in a single chest x-ray.
So, you now have a technical idea of what this test entails. Now, I am going to transcribe the instruction sheet that they gave me to help me prepare (can I say I am studying for my kidney test?):
Glofil Procedure - Patient Instructions
You have been scheduled for a Glofil Procedure, to determine your kidney function.
Your Glofil Procedure will last approximately 3 hours. You will be with a group starting at the same time. The first group starts at 7:00 am, and the second group starts at 11:45 am. If you cannot make your appointment, PLEASE let us know, so we can reschedule.
ALL LATE PATIENTS MUST BE RESCHEDULED.
You may eat a light meal (not heavy) up to 1 hour before your scheduled appointment.
You may drink water any time.
If you are on LASIX, you must take it more than one hour before your appointment.
If you were given a small vial of iodine (Lugol's Solution) when you made the appointment, you may take it the night before by mixing the contents of the vial in approximately one ounce of juice. Diet Coke tastes the best, if you have that.
You will want to arrive as hydrated at possible, by drinking plenty of water. We suggest 12 to 15 eight-ounce glasses of water each day. Do this for 3 days prior to your test, unless your physician instructs you otherwise or has orders for liquid intake restriction.
You are advised that nausea is a commonly experienced side effect due to the volumes of water administered during the test.
You will not be able to drink any liquid other than water during your appointment.
Fresh filtered bottled water is provided by our facility.
If you choose, you may bring at least one gallon of your own water for your test. The water may be cold but it must not have ice in it.
Lastly, avoid alcohol consumption at least three days prior to the test.
Therefore, in an effort to make your experience as pleasant as possible, please try to comply with all suggested requests prior to and during your Glofil Procedure.
When you arrive, we will need a fresh urine sample. Please plan accordingly.
If you have not taken our famous Lugol's Iodine cocktail the night before, we will give it to you at least 15 minutes prior to your Glofil injection.
You will be given a calculated amount of water to drink during your test.
As previously advised, the amount of water given may cause discomfort and even nausea. Please, let your technician know so we can make the appropriate recommendations.
You will be instructed to void urine and collect every drop and have blood samples taken at regular timed intervals during the three-hour test. Please, remain in the Glofil department during the testing. Advise your technician if you leave the area.
You must not eat during the test , unless instructed.
You should not have had anything to eat one hour prior to the test. This may cause nausea and additional un-needed discomfort.
Avoid any caffeine and tobacco products during testing.
You will not have a Glofil Procedure done if you are allergic to iodine. If you are allergic to iodine, your physician will order an alternate method.
You will not have a Glofil Procedure if there is any radiation present in your system. This would occur if you have recently had any type of scan or a stress test.
You will not have a Glofil Procedure if you are breastfeeding.
You should not have a Glofil Procedure if experiencing a menstrual cycle. We suggest that it be postponed.
If you are unable to make several trips to the restroom under your own power, you will need to bring someone with you to assist you.
Due to limited space, we ask that family members do not accompany patient in the Glofil waiting area, if fully occupied. Please use additional waiting areas provided so that we may accommodate all the scheduled patients. Any special requests regarding this may be discussed with the Glofil Technician at any time and we will certainly accommodate anyone if space is available.
If you have any questions or concerns, please call the Glofil Departmetn at xxx-xxx-xxxx ext 6269. Thank you, it is our pleasure to serve you.
So, there you have it. All my wonderful instructions. I guess I will start attempting to drown myself on Sunday or Monday, so that I am very well hydrated by Thursday afternoon. And, I have to remember to not eat after 10:30 on Thursday, and not to take my Prograf that day (though, that is because of my clinic appointment, not because of the Glofil Procedure).
I hope that information helped everyone understand what I will be doing next week. If you have any questions, feel free to post a comment or send me an e-mail!