Can a Spot Urine Replace or Improve 24 Hour Urine Collections in Kidney Stone Patients
Can a Spot Urine Replace or Improve 24 Hour Urine Collections in Kidney Stone Patients
This study will sought to determine if limited urine collections can provide similar or more
 informative data than standard 24-hour urine collections used to evaluate kidney stone
 formers.
BACKGROUND Urinary stone disease is a common problem, causing significant morbidity and
 sometimes mortality. Stone disease affects 5-10% of the population during their lifetime and
 of these patients between 30-50% will have at least one recurrent episode.

 Urinary stones arise due to crystallization and aggregation of supersaturated ion complexes
 in the urine. Depending on the concentration of various urinary constituents and the
 physicochemical characteristics of a given individual's urine (such as pH, volume, calcium
 citrate concentration etc.), different crystals may precipitate. Therefore therapy is
 tailored to the individual, based on stone composition and the results of the 24-hour urine
 collection. The majority of the stones are calcium based (calcium oxalate, calcium phosphate)
 while the remaining are comprised of uric acid, struvite, cystine or other substances.

 While some stones can pass spontaneously, the majority will require some form of treatment,
 and more than 50% will require surgical intervention. Until the 1980s, treatment of upper
 urinary tract stones often involved extensive open surgical procedures5. With the
 introduction of extracorporeal shock-wave lithotripsy (ESWL) and refinements in
 endourological procedures like percutaneous nephrolithotomy (PCNL), ureteroscopy (URS)
 techniques, it has now become possible to treat stones in almost all cases without open
 surgery. Stone management can be divided into three treatment phases. The first phase
 involves treatment of acute pain and the drainage of an obstructed and possibly infected
 kidney. The second phase aims to either remove or disintegrate the stone. The third phase is
 directed towards the prophylaxis of stone recurrence .

 The third phase involves the metabolic evaluation of the patient to identify possible risk
 factors for forming recurrent stones, which consists of a 24 hour urine analysis to determine
 the content of urinary components such as calcium or oxalate that play a major role in stone
 disease. High levels of oxalate and calcium contribute to kidney stones recurrences and
 therapy to reduce these two substances in the urine can reduce recurrence rates. Low levels
 of citrate also increase the risk for forming stones, and can be treated with alkali such as
 potassium citrate.

 Collecting 24-hour urines for evaluation and therapy can be cumbersome for patients and often
 leads to incorrect collection, which may be detectable by measuring the amount of creatinine
 in each sample. Previous attempts to evaluate spot versus 24-hour urines have been made, but
 more studies are necessary to determine how they compare to the conventional 24-hour
 collection. A more convenient method for collecting urine samples will facilitate the
 treatment and future prevention of recurrent kidney stone disease.

 The aim of this project is to determine whether spot urines collected separately at key times
 throughout the day are comparable to the conventional pooled 24-hour urine collection, and
 whether the former yield more accurate information in terms of the levels of urinary
 components. Perhaps a patient with normal values for a pooled 24-hour collection may show
 spikes in certain variables throughout the day that would not be discovered in the 24-hour
 sample. Furthermore, reducing the collection to a single time point would improve patient
 compliance making it easier to do subsequent follow-up collections.

 HYPOTHESIS AND OBJECTIVES We hypothesize that spot urines can provide equivalent information
 to that provided by a 24-hour urine test. An added benefit would be if spot urines provide
 more information for the identification of risk factors in patients who have normal 24-hour
 urine tests. A third possibility is that our hypothesis is incorrect and that a 24-hour urine
 sample will provide the most useful data in formulating a stone prevention therapy for our
 patients.
Inclusion Criteria:

 -  Patients who have been diagnosed as having calcium based urinary stones

 -  at least 19 years of age

 -  do not have any additional serious disease

 Exclusion Criteria:

 -  Patients who do not have calcium based urinary stones (such as: uric acid, cystine,
 struvite)

 -  less than 19 years of age

 -  have a serious alternate disease

 -  Pregnancy

 -  Positive Urine Culture

 -  Active cancer

 -  Recurrent urinary infections

 -  Gross hematuria

 -  Receiving treatment with thiazides (or alternatively can be enrolled if the patient is
 willing to stop treatment for 2 weeks prior to study)

 -  Inability to provide informed consent

 -  Investigator's refusal to include