Kidney Stone Prevention Programme

A programmatic approach to comprehensively treat kidney stone disease. Using this approach, we are able to reduce the rate of kidney stone recurrence up to 80%.

What do patients think about our service?

After experiencing the worst pain in my life and ending up in the hospital too many times to mention, I would wake up each day hoping not to have another episode. Then, I learned kidney stones could be prevented. After finding Litholink, I have not been to the hospital emergency room for the past 2 years. I learned how to take steps to prevent new stones. The Litholink program has helped me look forward to each stone-free day.

I lived in constant, excruciating pain, with at least one stone a month for the past 20 years. The stones also brought 2 surgeries, 4 lithotripsies, and visits to more than 10 urologists. I figured kidney stones were always going to be a part of my life, until I learned they could be prevented. Since starting the Litholink program, I have had no new kidney stones. I can’t thank my doctor and Litholink enough!

I had my first kidney stone at age 22. At 40, I was still producing stones and baffling all of my doctors. My last attack was while I was on vacation…not only ruining the trip for me, but for my family as well. It wasn’t until after we returned that I learned kidney stones could be prevented. Since starting my program with Litholink, I feel like I am finally in control. Knowing I can prevent future stones gives me the hope that I can live my life without the worry of them ruining my next vacation.

Frequently asked questions

About the test

  • What is the start time?

    Your “Start Time” is the FIRST time you urinate when you wake up to BEGIN the day.

    If you are doing two, 24-hour collections, the first day starts when you wake up to BEGIN the day. The first time you urinate, you flush it away. Although you do not collect this first urine in the collection container, this is the START TIME for day one. Collect all the urine you produce for the next 24 hours into the collection container.

    When you wake up on the second day of your collection, put that morning’s urine into the day one collection container. This time is the STOP TIME for day one and the START TIME for day two (use the same time for both). Collect all the urine you produce for the next 24 hours in the second collection container. At the beginning of the third day, put that mornings urine into the day two collection container. This is the STOP TIME for day two and the end of the entire collection.

  • Can I take vitamins or herbal supplements?

    It says in my instructions not to take any vitamin C five days before the test begins. Anything that your doctor has advised you to do, please continue. If you are taking supplements that contain 100mg or more of vitamin C and they have not been recommended by your doctor, please stop taking them 5 days before and during the collection process.

  • Should I continue to take prescription medication?

    Yes. All prescribed medications MUST be taken and will NOT alter the results of your test.

  • Can I complete the collection during my period?


  • There isn't enough room in my collection container

    Call our Customer Services team on 0800 036 2522. We refer to you as being a “high volume” (HV) patient. You drink and urinate more than other patients. Unfortunately, you may not realise this until you are in the middle of the collection process. In this case, STOP collecting and start a new collection. You must call Cellmark and state that you need a HV collection kit.

    A high volume kit contains: 2 collection containers per 24-hour collection, 2 urine preservatives per 24-hour collection, 2 green-topped tubes per specimen, and special HV instructions.

  • What happens if I’m not at home and I have to go to the bathroom?

    If this happens, just carry any small, clean container to urinate into. You have up to 8 hours to get the urine back into the collection container that has the preservative in it.

  • There are small, black specks inside my collection container

    Those “specks” sometimes occur because the print from the preservative tube label comes off when exposed to liquid. This will not interfere with the test.

  • Do I need to refrigerate my urine?

    No. A urine preservative is provided for each collection container. The preservative keeps the urine free of bacteria. If you put the collection container into the refrigerator, the sample(s) will be rejected. Refrigerated urine leads to less accurate results because stone forming salts become crystallized (from the cold) and thus the results are less viable.

  • I received my kit, but I am sick.

    Your test results are reflective of what you consume in each 24-hour period. Kidney stone disease can be a result of one’s diet and fluid intake. Therefore, it is important to eat and drink as you normally do. If you are not feeling well, you may not be eating and drinking as you normally do. So please wait to start your collection until you are feeling well enough to eat and drink as you normally do.

  • I am doing the two-day collection, do I need to do it on a working day?

    Try and do this on a working day and a non-working day. Generally, people eat and drink differently on workdays and non-work days. We understand that not everyone can do the collection during working hours. In this case, do the collection on two non-working days (usually this is Saturday and Sunday), but on one of those days, mimic what you would normally eat and drink during a workday. This gives us a more accurate representation of your overall diet and fluid intake.

  • I forgot to collect my urine in the night, are you going to reject my test?

    I'm afraid so. You need to collect all urine, even in the middle of the night. Any collection period that lasts less than 22 hours or more than 26 hours will be rejected.

  • I am doing the two-day collection. Do I have to do the collection two days in a row?


  • Should I drink more when I take my test?

    No. Do not change your fluid or diet routine. We want to see why you have been forming stones. Any diet or fluid changes should take place after you finish your collection.

  • Is the preservative poisonous?

    The preservative does contain toxic chemicals, just like many household cleaners, and should be handled with caution and kept away from children and pets. If you get it on you wash the area with soap and water. Don’t flush the plastic bottle down the toilet, we encourage you to pour carefully or use the spout when you discard the left over urine specimen into the toilet. It will not harm the toilet.

  • I have finished the collection. What do I do now?

    Post the sealed box back to our laboratory the same day.

    The urine preservative’s effectiveness expires after a certain amount of time, so we need to get the sample(s) sent back to us immediately. If we do not receive your sample(s) in a timely manner, we will reject your sample(s). If you have questions, please call our Customer Services team on 0800 036 2522.

About the diagnosis

  • My doctor says I have hypercalciuria. What is this?

    Hypercalciuria is the medical term for high urine calcium. Many men and women who have calcium kidney stones are found to have high levels of calcium in their urine. Hypercalciuria is genetic and runs in families. For more information about hypercalciuria click here.

  • My doctor says I have hypocitraturia. What is this?

    Hypocitraturia is the medical term for low urine citrate. Citrate is a molecule in blood and urine that binds to calcium. When citrate binds to calcium in the urine, it acts like a shield by preventing calcium from binding with oxalate or phosphate. If your citrate is low, your shield is weak. Calcium is then free to bind with oxalate and phosphate (which are common stone compositions), thus leading to new stone formation.

  • My doctor says I have hyperoxaluria. What is this?

    Hyperoxaluria is the medical term for high levels of oxalate in the urine. There is no known function of oxalate in animals, but it is believed to help plants dispose of excess calcium. The most common type of kidney stone is made of calcium and oxalate. The sources for oxalate include:
    • Eating foods high in oxalate
    • Intestinal over-absorption (patients who have had ileal resections due to inflammatory bowel disease)
    • Waste product of general metabolism
    • Excess amounts of vitamin C (2000 mg or more per day)

  • What effect does bowel disease and/or intestinal surgeries have on my kidney stones?

    There is a definite correlation between patients who suffer from bowel disease and mal-absorption problems and the formation of kidney stones. Urine is more acidic, citrate levels are lower, and oxalate levels are much higher. If you have had an ileal resection you may experience an increase in your oxalate levels due to mal-absorption problems.

    In bowel disease, fatty acids and bile that are normally absorbed by the small intestine reach the colon. When fatty acids and bile reach the colon, they can damage the colon lining allowing oxalate to pass through the damaged lining into the blood, and then into the urine via the kidneys.

  • My doctor says I have hyperuricosuria. What is this?

    Hyperuricosiuria is the medical term for high levels of uric acid in your urine. Excessive intake of animal protein can lead to these higher levels. After you metabolize animal protein, it breaks down into chemicals called purines, which then break down further into the waste product uric acid. There are also some patients who simply produce more uric acid than others, regardless of their protein intake.

    If your urine contains high levels of uric acid, this could be the reason you are forming 100% uric acid stones or mixed uric acid/calcium oxalate stones. Uric acid causes a decrease in calcium oxalate solubility and an increase in formation of uric acid and/or calcium oxalate crystals. If your high urine uric acid is lowered, new stones are less frequent.

  • My doctor says I have a low urine pH. What does that mean?

    A normal urine pH is about 6.0. H is the unit of measure used to describe acid-base balance. If your urine pH falls under 5.8, it is considered to be low and your urine is more acidic. When your urine pH is low, uric acid crystals will form and this will lead to either uric acid stones or mixed calcium oxalate/uric acid stones. Citrate and urine pH seem to be dependent on one another as well: low urine pH, low citrate.

    A low urine pH may be related to a genetic trait. It is also prevalent among people who suffer from bowel disease or kidney disease.

  • My doctor says I have a low urine output. How much water do I need to drink every day?

    The single most important thing you can do to help in the prevention of future kidney stones is to increase your daily fluid intake. Water is best. You should be producing at least 2 liters of urine per 24-hour period. If you do not drink enough fluids, crystals may form in your urine and be deposited on the inner surface of one or both kidneys. Stones will form as these crystals combine together. The color of your urine is a good indicator in determining if you are taking in enough water. If your urine is a dark yellow, you need to be drinking more. If your urine is clear like water, you are on the right track!

Information about kidney stones

General information

  • Can kidney stones be prevented?

    Yes, kidney stones can be prevented!

    During the last 30 years, treatment plans incorporating diet, fluids, and medications have been developed to prevent or stall the formation of new stones. The primary treatments have been proven in controlled clinical trials.

    Your preventative treatment may consist of fluid, diet, and/or medications. It is then up to you to follow your treatment every day. Fluid and diet changes are just as essential as any medications your doctor may prescribe. Stopping your treatment will cause your chemistries to go back to a stone forming state within DAYS.

  • What causes kidney stones?

    Kidney stones form when urine has too many crystal-forming chemicals and/or not enough substances that protect against crystal formation. If the crystals do not rapidly pass through the urinary tract, they can grow and form stones. When the volume of urine is too low, stone-forming materials become concentrated, helping to promote stones.

  • What did I do to cause my stones?

    Genetics, diet, fluid intake, work environment, and even geographical location are all factors which may influence the formation of stones.

  • What exactly are kidney stones?

    Kidney stones are hard objects made of a solid crystalline material imbedded in proteins usually present in urine. Most stones form on the interior surfaces of the kidney at the site where the final urine leaves the kidney tissue and enters the hollow collecting system that will take it down to the bladder. Because they form on the kidney surface, stones are often without symptom and are found by x-ray undertaken to determine unexplained blood in the urine. Though anchored to the kidney, these hard objects cause local injury and bleeding that doctors detect with routine urinalysis.

    When a stone breaks loose of the place it formed on, it falls into the urine collecting system and may attempt to pass through into the bladder. Small stones, less than 5mm in size, usually pass through. Those above 7mm usually do not. Either way, a stone that attempts to pass can produce extreme pain, bleeding, and obstruction of the kidney it is passing from. The pain is what most often signals stone disease to a patient.

    The kind of material the stone is made of determines an important part of diagnosis and treatment; therefore all stones should be collected and analyzed whenever possible.

Types of kidney stones

  • Calcium Oxalate Stones

    The most common kidney stone is made of Calcium Oxalate. Calcium is a main constituent of bone, and is always present in blood and urine. Oxalate is a by-product of metabolism and is also present in many foods. When they combine in the kidneys, calcium and oxalate produce a very insoluble salt that easily forms a solid stone. Once they form, these stones can never dissolve and must be passed or broken up by a surgeon using modern technologies.

  • Calcium Phosphate Stones

    Less common are Calcium Phosphate stones. Calcium Phosphate crystals are the stiffener that makes bone rigid. Large amounts of phosphate from food are eliminated in the urine of normal people everyday. The usual cause of calcium phosphate stones is a disease that increases urine calcium and also makes the urine abnormally alkaline. When the urine is not alkaline, high urine calcium concentrations produce mainly calcium oxalate stones, but when the urine is alkaline, calcium is bound by urine phosphorus, and calcium phosphate stones are produced. Minor amounts of calcium phosphate are usual in calcium oxalate stones and have no clinical significance. When the bulk of the stone (more than half) is calcium phosphate special treatment is often needed.

  • Uric Acid Stones

    Also less common but very important are stones made of uric acid. These can either be pure uric acid or a mixture of uric acid with calcium oxalate. Uric acid is a breakdown product of DNA and RNA, and crystallizes into stones whenever the urine is chronically acid in character. Uric acid stones can dissolve if the urine can be made to be less acidic. The causes of abnormally acidic urine include heredity, gout, renal disease and intestinal disease, as well as dietary extremes.

  • Struvite Stones

    Stones composed of struvite (magnesium, ammonium, phosphate) are always produced by infection. Some bacteria that infect the kidneys and urinary tract can break down urea, a universal constituent of urine, to ammonia. The ammonia makes the urine in the vicinity of the bacteria extremely alkaline, and the normal amounts of magnesium and phosphorus present in all urine form crystals with dissolved ammonia and make this serious and large type of stone. Unlike calcium oxalate and most calcium phosphate stones, struvite stones can rapidly grow so large as to fill the entire interior of the kidney drainage system. There are two types of struvite stone-forming patients and they require completely different treatments.

  • Cystine Stones

    This uncommon stone is made of the amino acid cystine and occurs only in patients who have an inherited disease called cystinuria. Urine can dissolve no more than 300mg of cystine in a liter, and normal people lose less than 100mg daily in their urine. Cystine is present in blood and filtered from blood by the kidney in very large amounts. People with cystinuria lack the renal mechanisms to reclaim filtered cystine back into the blood. This valuable nutrient is lost in the urine, and makes large and potentially dangerous stones, often beginning in infancy or childhood. The Litholink panel of tests screens all patients for cystinuria. Those who have it require very specialized testing and treatment. 

  • Unusual Stones

    Certain anti-viral drugs as well as triampterine (a diuretic) are well known to cause kidney stone formation. 2-8-hydroxyadenine stones form in people who have a very rare inherited enzyme deficiency that causes over production of the material.

Diet Information

  • Increase fluid intake
  • Low oxalate diet
  • Low salt diet
  • Low purine diet
  • How much water should I be drinking each day?

    A very common question is! You should be producing at least 2.5 liters of urine a day. How much you need to produce that much urine will vary depending on many things.

    Activity level (the more active you are the more you perspire and need to replenish your body with fluids).
    Living/working in a hot/dry environment.
    Frequent Flying (pilots, flight attendants, business travelers, etc.) Flying all day can cause dehydration.
    Salt intake (high salt intakes increases water retention). Increasing your fluid intake keeps urine diluted and helps keep crystals from forming.

    Click this link to download our advice leaflet

  • Everything in moderation

    Unfortunately, oxalate is found in healthy plant foods. What can become confusing for some patients is that they have already been put on dietary restrictions because of other medical conditions (e.g., heart related problems, diabetes, high blood pressure, etc.). You may have been told by another physician to “eat a diet low in fat and sugar but rich in vegetables.” What now? The key to diets is: Everything in moderation! If you have been told to “watch your oxalate intake,” remember to cut back on the portion size of the high oxalate containing foods and the number of times a day or week you are eating these foods. Here and there you will indulge, and when you do, make sure you flush out the extra oxalate with an added 8 oz. glass of water – before and after your treat!

    Click this link to download our advice leaflet

  • Your sodium intake should be 2300-3300 mg per day.

    We receive phone calls from patients who swear they have stopped using the saltshaker and they just don’t understand how their sodium levels remain so high. Unfortunately, sodium has been added to many of our foods that we buy in restaurants or at the store. A single restaurant meal can contain anywhere from 1000 to 4000 milligrams of sodium! It is important to read the nutrition labels on all packaged foods and to look at the ingredients listed. All food labels list the product’s ingredients, in order, by weight. The ingredient present in the greatest amount is listed first. As a rule, if salt and several sodium compounds are listed as ingredients, the product contains more salt than is advisable on a low-sodium diet.

    Click this link to download our advice leaflet

  • Linked to high protein diets

    In order to reduce your uric acid level, you must lower your consumption of purines. Purine is a compound that is mainly found in animal protein and when metabolized breaks down into uric acid. When you eat a diet that is high in protein (beef, poultry, pork and chicken), you have higher uric acid levels. The normal diet contains from 600 to 1000 milligrams of purines daily. A low-purine diet is restricted to approximately 100 to 150 milligrams daily.

    Click this link to download our advice leaflet

Cystine stone testing

Cystinuria, which occurs only in 1-2% of kidney stone patients, is one of the most serious forms of kidney stone disease. Cystinuria is an inherited metabolic disorder in which excessive amounts of the amino acid cystine enters the kidney, forming what are called “cystine stones”. Cystine stones are large, difficult to treat, and can severely damage the kidney. Unfortunately, it is the most common stone produced by children and many have suffered permanent kidney damage as a result of this terrible disease.

Children require special care and evaluation.  Litholink is pleased to be able to offer the only commercially available, patented testing method that allows accurate results even while patients are taking their current cystine medication.The scientific and technological basis for the test was first reported by Dr. Fredric L. Coe, Litholink founder and Professor of Medicine at the University of Chicago Pritzker School of Medicine, and Dr. John Asplin, Litholink’s Medical Director, in August 2001 in the Journal of Urology (Solid Phase Assay of Urine Cystine Supersaturation in the Presence of Cystine Binding DrugsJournal of Urology, Vol. 166, pp. 688-693 (August 2001.)  Litholink has now been successful in making the test reliable, efficient, and available for the broader physician community.