Urinary Stones or Urolithiasis is a common, painful and destructive disease. It has a habit of recurrence. About half of Stones recur with in 5 to 7 years of first episode. Stone disease tests are very useful to know cause of Stone formation. This is essential for focal prophylactic treatment to prevent recurrance.

1. Dr. Sanjeev Mehta MDDr. Sanjeev Mehta MD
Ahmedabad, INDIAAhmedabad, INDIA
www.urolab.net
Metabolic Evaluation
&
Stone Analysis
Practical implications

2. Role of laboratory
• What lab can not tell you, you will not
know.
• What it tells you in error, you will not
correct by using your instincts, your
medical experience or your art.
• Misdirected treatment : unreasonable
expenses.
• The Kidney Stone Handbook; Gail Savitz & co auth.

3. Stone : Supersaturation of Urine

4. Stone Promoting and
Inhibiting Factors
PROMOTORS INHIBITORS
Calcium Inorganic : Magnesium
Sodium Phosphorus
Oxalate Citrate
Urate Organic : Nephrocalcin
Cystine Tomm-Horsfall Protein
Low Urine Ph Urinary Prothrombin fragment.
Tomm-Horsfall Protein
Bacterial products

5. Evaluation of Stone Disease
ROUTINE BLOOD AND URINE TESTS
STONE ANALYSIS.
24 HRS URINE METABOLIC PROFILE
New advances in Stone analysis, Blood and Urinary
Chemical analysis can find out 90-95% cause.

6. Clinical usefulness
1.Identify treatable metabolic abnormality
2.Identify underlying medical disease that
predisposes to stone formation.
3.Outline a treatment plan.

7. A. Routine Tests
BLOOD
low K, and HCO3- RTA
High Uric acid - Uric acid
diathesis
High Calcium- pri
hyperparathyroidism
Low phosphorus- renal
phosphorus leak.
Parathyroid ; sos
URINE
pH > 7.5 – infection
lithiasis
pH < 5.5 – Uric acid
lithiasis
Sediments for
crystalluria
Urine culture
Qualitative cystine

8. Renal Stone Analysis
• Essential step in the examination and initial
treatment of Urolithiasis.
• Yields fundamental information about ;
- Metabolic abnormality.
- Presence of infection.
- Possible artifacts.
- Drug metabolism.

9. Technique
Integrated
analysis with
Infra-red
spectrometry
Xenthene and
Ca.oxalate
Dihydrite

10. INTEGRETED
ANALYSIS ;
Mixed Stone

11. 11
Actually up to 65 different chemical
compounds are found in urinary calculi.

12. Clinical significance of Stone
analysis
• Three categories :
1.Composition and hardness of Renal
Stones.
2.Composition and its predictive value.
3.Composition and related metabolic
abnormalities.
Kourambas J, Aslan P, Teh CL, Mathias BJ, Preminger GM.J Endourol. 2001
Mar;15(2):181-6

13. Clinical Significance: Hardness
pattern in Stone.
• Useful in describing consistency in individual.
• Formulation of treatment strategies.
- Number of re-treatments.
- Number of Shock waves.
• Energy index (KV x number of shock waves).
Ringdén I, Tiselius HG, Scand J Urol Nephrol. 2007;41(4):316-23

14. Hardness Factor of Stone
Calcium Oxalate Dihydrate 1.0
Calcium Oxalate Monohydrate 1.3
Hydroxy-peptite 1.1
Brushite 2.2
Uric Acid/ Urate 1.0
Cystine 2.4
Carbonate Apatite 1.3
Struvite 1.0
Mixed Stone 1.0
* Ringden I, Scand J Urol Nephrol.2007;41(4):316-23

15. Clinical value : Calcium
• Present in approximately 80% stones.
• Combines with phosphate or oxalate or both.
• Risk factors : hypercalciuria,
Hyperoxaluria.
hyperuricosuria.
predominantly acid or alk urine.
hypocitraturia.
low urine volume.

16. Calcium Stones …..
Pure calcium Stones
• More Acid urine
• Low Urine volume
• High Oxalate
excretion
Mixed Stone formers
• pH is higher
• High Calcium
• High Calcium
excretion
• High recurrence rate
* Schroeppel j Smith et all ; J Am Soc Nephrol
1997;8:568A

17. Calcium Stone…..
Ca-oxalate Monohydrate
• Hypo- megnesuria
• Acidic Urine
• Low Urine volume
• Hardness +
• Ca-ox Dihydrate
• Hyper-calciuria
• Alkaline Urine
• Hypo-citraturia
• Hardness ; less

18. Renal tubular acidosis
Carbonate apattite
• Consider RTA
• Increases with amount
• (5-39%)
Brushite Stones
• Consider RTA

19. Struvite Stone
Magnesium Ammonium Phosphate
• Mixed Stone : Infection.
‘Proteus’
• Strains of staphylococci, pseudomonas and
kelbsiella.
• Rarely; E.coli.
• Urine Ph. Is < 7.5

20. Ammonium Urate
• Calcium oxalate – containing calculi, may start
hyperuricosuria.
• Elders : associated with infection.
• Children : May as result of hyperuricosuria,
but No UTI

21. Brushite : Amm. Calcium
Phosphate
• Sizable stone burden. Increasing trend
• High recurrence rate , 3 yrs
• Familial tendency
• Hypercalciurea and underlying metabolic
abnormality.
• Extreme Alkaline Urine.
J Urol. Oct 2010; 184(4): 1367–1371.

22. Dahilite ( Carbonate apatite)
• Phosphate stone
• Infection in body.
• May not accompanying sign of disease.
• RTA
• Disorder of phosphate metabolism.
• Rare in pure form ( 2-3%).

23. Uric Acid
URIC ACID
• Hyperuricemia, hyperuricosuria.
• Low Urine Ph. < 6.2
• Causes:
- Gout.
- Myeloproliferative dis.
- Chemotherapy and
Radiotherapy.

24. Cystine
CYSTINE
• Cysteinuria.
• Autosomal recessive
disorder.
• Occurs predominantly
in pure form.
• XENTHENE
Most frequent causes:
- Xanthinuria.
- Absence of Xanthene
oxidase.
• Genetic autosomal
hereditary recessive
enzyme disorder.
• Trigger : Allopurinol
Treating Gout.

25. Urine: Metabolic Evaluation
24 hrs Urine collections: multiple parameters
Stone risk factors : Quantitation
Volume and pH
Calcium
Oxalate
Citrate
Uric acid.
Creatinine

26. Metabolic Evaluation: 24 hrs
Urine
• Dietary risk factors:
Sodium,
Potassium
Magnesium
Urinary analysts : phosphorus, sulphate, Urea
Children : state sample
Repeat 24 hrs Urine collection 4-6 weeks post
interventi

27. GOLD STANDARD
Supersaturation
value.
•High risk parameter
can be monitored.
Graphic presentation

28. Super-saturation : Gold standard….

30. Conclusion
• Advancement in laboratory can now diagnose
cause of stone formation uo tp 90% cases.
• By appropriate Stone analysis and metabolic
evaluation can effectively treat impact of
Nephrolithiasis and prevent recurrence .

31. Conclusion: Significance
• Advancement in laboratory can diagnise cause
of Stone disease up to 90%
• Impact mitigated by appropriate metabolic
evaluation.
• Identify risk factor.
• Focused medical treatment
• Significantly reduces recurrence
• Social and financial burden.
• Batter quality of life

32. Thank you !
For further details
contact:
sanjeev@urolab.net
Phone: +91 79 40380380