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Blood Test for Kidney Stones: How Does It Work?

Medically Approved by Dr. Edward Salko

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man holding himself in pain from kidney stones

Kidney stones, clinically referred to as renal calculi, are composed of hardened mineral and salt deposits accumulated in the kidney during blood waste filtration. While imaging tests like CT scans and ultrasounds reveal their presence, size, and location, individuals can benefit from a blood test for kidney stones as they help identify underlying metabolic conditions that lead to their formation. Here are lab procedures that can help address kidney stones. 

Blood Tests Involved in Kidney Stone Detection

Blood tests for kidney stones can range from metabolic lab assessment to waste ratio identification. Information derived from these tests can guide healthcare providers in forming personalized treatment strategies. It also prevents future stone formation, ensuring comprehensive care for individuals with kidney stones. The following are the blood tests for kidney stones: 

  1. Calcium blood test

A calcium blood test measures the level of calcium in your blood, which can show potential imbalances contributing to stone formation. High calcium levels (hypercalcemia), in particular, may indicate an underlying condition like hyperparathyroidism or other metabolic issues that increase the risk of calcium-based kidney stones, the most common type.

Did You Know? Essential blood tests for kidney stones are included in the basic metabolic panel (BMP) and comprehensive metabolic panel (CMP). These bloodworks are not just designed as diagnostic tools but as part of regular checkups.   

  1. Phosphorus blood test

While not a primary blood test for kidney stones, a phosphorus blood test helps assess the risk and potential causes of calcium-based kidney stones. Calcium and phosphorus levels in the body are closely linked. Therefore, irregularities involving this mineral may exacerbate its development. 

For example, elevated phosphorus levels(1) can trigger the release of parathyroid hormone. This can increase calcium in the blood and urine, making calcium stones more likely.

  1. Electrolyte blood test panel

An electrolyte panel quantifies the levels of key minerals in your blood, like sodium, potassium, calcium, and chloride. These minerals help maintain fluid balance and the proper functioning of your kidneys. Imbalances in these electrolytes can trigger kidney stone formation, as discussed with calcium above.

  1. Uric acid blood test

Uric acid is a waste product produced when your body breaks down purines. High uric acid levels (hyperuricemia) can lead to the development of uric acid crystals, which form kidney stones. Thus, a uric acid blood test can help detect hyperuricemia, which may indicate a need for dietary changes or medication to lower uric acid levels and prevent future stones. 

Additionally, if a kidney stone is found through imaging, the uric acid test can help confirm whether it’s a uric acid stone or another type. This aids in guiding treatment and prevention strategies.

Pro tip: An elevated uric acid can stem from a combination of external and internal factors. However, there are natural ways to lower high uric acid levels. Read our guide to know more.  

Additional Tests 

Aside from the primary tests that help show kidney stones, your healthcare provider may request additional lab work to have a more comprehensive evaluation of the condition. These blood and urine tests for kidney stones may include a urinalysis, creatinine blood test, BUN test, CBC, and PTH. 

Urinalysis

Urinalysis provides valuable information about the composition of the urine and can reveal abnormalities indicative of stone formation. Specifically, urinalysis can detect the presence of microscopic blood (hematuria)(2), a common indicator of kidney stones, as well as crystals and minerals that may contribute to their development. Furthermore,  the test can identify any signs of infection, a potential contributing factor to certain types of stones.  

Creatinine blood test

The creatinine blood test provides insights into kidney function, a key factor in the buildup and potential complications of kidney stones. Elevated creatinine levels may signal impaired kidney cells, which can encourage stone formation due to the kidneys’ reduced ability to filter waste products effectively. Furthermore, monitoring creatinine levels helps assess the overall impact of kidney stones on kidney health and guides treatment decisions.

Blood urea nitrogen (BUN) test

A BUN test may not be a primary diagnostic tool or kidney stones themselves. However, it provides crucial information about your renal function, which can help reveal issues related to kidney stones. BUN measures another waste product filtered by the kidneys called urea nitrogen. 

High BUN levels may suggest kidney problems, which may be caused by obstruction due to a kidney stone or complications arising from the stone, such as infection or hydronephrosis (kidney swelling). 

Complete blood count (CBC)

A complete blood count or CBC can detect signs of infection, which may be associated with certain types of kidney stones or can arise as a complication of their presence.  Additionally, the CBC assesses red blood cell levels, which can indicate anemia, a potential consequence of chronic kidney disease that may accompany recurrent stone formation.  

Parathyroid hormone (PTH) Level

PTH has a part to play in calcium regulation, and its measurement is essential in evaluating patients with suspected kidney stones, mainly when elevated calcium levels are detected in blood tests. PTH, secreted by the parathyroid glands, increases calcium levels in the blood by promoting calcium release from bones and increasing calcium absorption in the intestines.  

Therefore, an elevated PTH level(3) may indicate hyperparathyroidism (even after a curative procedure), where the parathyroid glands produce excessive PTH. This can lead to hypercalcemia and an increased risk of calcium-based kidney stones.

When to See a Doctor

Seek urgent medical care if you experience severe pain in your back or side that comes in waves and fluctuates in intensity, especially if it comes with nausea, vomiting, or blood in your urine. These symptoms often indicate that a stone obstructs the urinary tract, potentially leading to complications. Additionally, seek prompt medical attention if you have a fever or chills along with pain, as this could signify an infection.

Kidney Stone Causes and Complications

It is said that 1 in 11 people(4) experience kidney stones sometime in their lives. This prevalence is often associated with unhealthy habits that promote waste crystallization in the kidney. Nonetheless, your susceptibility to forming these stones depends on lifestyle factors mixed with genetic predisposition. Specifically, kidney stone formation can be due to the following conditions:

  • Dehydration: Not drinking enough fluids is a major culprit. When dehydrated, your urine becomes more concentrated, making it easier for minerals to crystallize.
  • Dietary Habits: High sodium intake, in particular, can increase calcium excretion in the urine, while diets rich in oxalate(5) (found in certain vegetables like spinach and rhubarb) or animal protein can also contribute to stone formation.   
  • Family History: A familial predisposition to nephrolithiasis is a significant risk factor for the development of the condition. Genetics can influence how your body processes minerals and predispose you to stone formation.   
  • Medical Conditions: Certain medical conditions, such as hyperparathyroidism (an overactive parathyroid gland), gout, inflammatory bowel disease, and urinary tract infections, can increase your risk of developing kidney stones.   
  • Medications: Some medications can also increase the risk of kidney stone formation. These may include certain diuretics, medications used to treat migraines or seizures, and even some over-the-counter supplements. Thus, it’s imperative to let your healthcare provider know about the ones you’re taking.

Detection of kidney stones is not enough to address this issue. Finding out how it was formed is the most important part of securing the proper treatment and tailoring preventive measures for your condition. 

Frequently Asked Questions

Does CBC show kidney stones?

CBC is more of a complementary tool in detecting kidney stones, which means that while it does not reveal the stones on their own, it helps identify the potential causes and complications associated with them. Instead of a CBC, an imaging test along with some blood tests may be ordered to accurately show the presence of kidney stones. 

Where do you feel kidney stone pain?

Kidney stone pain is typically felt in the flank or side, between the ribs and hip. This pain, often described as sharp and cramping, can radiate to the groin or lower abdomen as the stone moves through the ureter, the tube connecting the kidney to the bladder. The intensity of the pain can fluctuate, coming in waves as the muscles in the urinary tract try to push the stone along. 

What dissolves a kidney stone fast?

Unfortunately, there’s no magical cure for kidney stones that can eradicate it in an instant, but for smaller ones (typically under 5mm), increased hydration can be a game-changer. Drinking plenty of water, along with refreshing citrus juices like lemonade, can encourage urination and potentially help flush out these pesky stones.

The Bottom Line

It’s no secret that imaging techniques visualize the kidney stones themselves. However, blood tests offer a deeper understanding of the biochemical processes involved. Furthermore, blood work assesses kidney function and detects potential complications associated with kidney stones. If you observe any symptoms associated with kidney stones, seek medical attention as early as possible to ensure rapid action and a more personalized approach to treatment. 

Sources

1 Shaker JL, Wermers RA. The Eucalcemic Patient With Elevated Parathyroid Hormone Levels. J Endocr Soc. 2023 Jan 26;7(4):bvad013. doi: 10.1210/jendso/bvad013. PMID: 36793479; PMCID: PMC9922947.

2 Nagendra V, Dhande R, Mishra G, Reddy NG, Gowda H. Hematuria as a Sign of Kidney Stone Disease Evaluated Using Computed Tomography: A Review. Cureus. 2023 Apr 24;15(4):e38064. doi: 10.7759/cureus.38064. PMID: 37252589; PMCID: PMC10212727.

3 Dream S, Kim GY, Doffek K, Yen TW, Carroll T, Shaker J, Evans DB, Wang TS. Persistent elevation of parathyroid hormone after curative parathyroidectomy: A risk factor for recurrent hyperparathyroidism. World J Surg. 2025 Jan;49(1):148-158. doi: 10.1002/wjs.12413. Epub 2024 Nov 17. PMID: 39551628.

4 Leslie SW, Sajjad H, Murphy PB. Renal Calculi, Nephrolithiasis. [Updated 2024 Apr 20]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK442014/

5 Chen T, Qian B, Zou J, Luo P, Zou J, Li W, Chen Q, Zheng L. Oxalate as a potent promoter of kidney stone formation. Front Med (Lausanne). 2023 Jun 5;10:1159616. doi: 10.3389/fmed.2023.1159616. PMID: 37342493; PMCID: PMC10278359.

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