If you're at risk for kidney stones or you've already experienced one of these painful little buggers, your urologist has likely drawn blood for a metabolic workup at some point. (A metabolic workup is more formally known as a comprehensive metabolic panel or CMP.)
But what is a metabolic workup for kidney stones? We asked Victoria Webber, a physician assistant in our Plymouth Care Center, to share her insights.
As with all content on our blog, the following is educational, not medical advice. Always consult your medical provider regarding your unique healthcare needs.
VICTORIA WEBBER: A metabolic workup is a series of blood tests and a urine test for patients with a history of kidney stones that we deem to be "high risk" for developing recurrent stones or complications from stones.
Metabolic workups help us determine if there is an underlying disorder causing stone formation and guide us in preventing future stone formation through changes in diet or medications.
The metabolic workup for kidney stones includes the following:
Blood tests:
24-Hour Urine Test: The patient collects urine for 24 hours and brings it to a lab to be analyzed for total urine volume, citrate, oxalate, calcium, sodium, uric acid, phosphate, and other levels.
VICTORIA WEBBER: The first value I always check is a patient's urine output since dehydration is the most common cause of stone formation. (Test your kidney stone knowledge here.)
VICTORIA WEBBER: The information we learn from the metabolic workup is vital for managing high-risk stone patients. This high-risk demographic includes the following:
VICTORIA WEBBER: You shouldn't change your diet or fluid intake before completing the metabolic workup since this could affect your results and "cover up" the reasons you're forming stones.
Remember, a metabolic workup aims to get an accurate baseline to determine what has likely been causing the stone formation. For example, if you change your diet on the day of the 24-hour urine collection, the results will not be helpful.
You should plan to do the urine test on a day when you can spend most of your time at home since you won't want to carry a jug of urine around with you all day.
You should also wait at least one month after the last stone event (i.e., surgery for kidney stones or passing a stone) before completing a metabolic workup since this will cause inaccurate results due to the recent stress on your kidneys.
VICTORIA WEBBER: I know it can be tempting, but don't try to interpret these results on your own. Review them with your healthcare provider because the results can be difficult to interpret and aren't always straightforward. We interpret the 24-hour urine and blood work results together (one informs the other).
VICTORIA WEBBER: The initial metabolic workup provides a baseline. If any changes are made (medications or lifestyle modifications, for example), we can repeat the workup after six months and as needed.
VICTORIA WEBBER: If you're a recurrent stone former and looking for ways to prevent future stones, discuss obtaining a metabolic workup with your provider. We're accepting new patients at GBU, so if you're in Massachusetts, feel free to reach out.
Request an appointment at one of our convenient care centers.