The following is a guide for the investigation of patients who have passed a renal stone:
A. Analysis of the Stone:
Send it to the laboratory. The composition of the stone may be helpful in identifying the cause of its formation.
B. Blood Tests: 5 mL blood in a heparin tube. Request the following tests:
-
Na, K, Cl
-
Urea, Creatinine
-
Calcium, Phosphate
-
Albumin
-
Urate
-
Parathyroid Hormone (PTH) if calcium is high or in patients with CKD
-
Venous Bicarbonate
-
Liver enzyme tests
C. Spot urine (mid-stream) is recommended:
-
pH
-
Microscopy for Red Cell Count, White Cell Count
-
Microscopy for presence of crystals
-
Urine culture
-
Cystine
D. 24 hour urine tests are not usually necessary for a single stone episode, but should be done for recurrent stones.
Request the following tests:
-
pH
-
Volume
-
Urea, Creatinine
-
Sodium, Potassium, Calcium, Phosphate, Magnesium
-
Oxalate, Citrate
-
Urate
Preferred specimen is thymol-bottle
which is available from LabPlus or LabTests Auckland (LTA)'s designated collection centres in the community.
Store at room temperature and
deliver to LTA's designated collection centres (or LabPlus Specimen Reception) within 6 hours of completion
.
Collection requirements and contact details of LTA Collection Centres can be found by downloading the two attachments below - Links above.
The Guide for interpreting 24 hour urinalysis for kidney stones: adults - Links above.
NOTE:
(Plain or HCl containing bottles may be used under occasional circumstances, but unable to deliver a full test repertoire -
not recommended
).
E. For children
Random urine samples are acceptable, if they are sent to the laboratory without delay. Acidification of the sample will be performed by the laboratory.
Please state "renal stone" on the form and request::
-
Calcium, Oxalate
-
Creatinine
-
Urate
-
Cystine
-
Citrate
-
pH
F. If renal tubular acidosis is suspected, submit
a) Venous or arterial blood taken in a heparinised blood gas syringe for:
b) Random urine for pH and Ammonia.
Emails to
chemicalpathologist@adhb.govt.nz
will receive priority attention from the on-call chemical pathologist.
If the query concerns a specific patient please include the NHI number in your email.
If email is not a suitable option, please contact the on-call chemical pathologist via
Lablink (Auckland City Hospital ext. 22000 or 09-3078995).
Individual chemical pathologists may be contacted but will not be available at all times.
After-hours
: contact
Lablink (Auckland City Hospital ext. 22000 or 09-3078995) or hospital operator for on duty staff after hours.
Dr Samarina Musaad
(Clinical Lead)
:
SamarinaM@adhb.govt.nz
ext. 22402
Dr Cam Kyle:
CampbellK@adhb.govt.nz
ext 22052
Dr Weldon Chiu:
WeldonC@adhb.govt.nz
ext. 23427
Dr Campbell Heron:
CHeron@adhb.govt.nz
ext. 23427
Dr Sakunthala Jayasinghe:
Sakunthala@adhb.govt.nz
ext. 23427