hospitals rely on high tech, expensive and sometimes invasive tests to make a
diagnosis. One of the most basic and cheapest tools we have at our disposal is
the bedside urine ‘dipstick’ test. What can we learn from such an easy to
(Pinnacle 10SG Urinalysis).
urine specific gravity and osmolality and on urine albumin and protein measurements
using the ‘dipstick’ test. Here’s what else this bedside test can help you with.
exposed to the peroxide and a chromagen on the test pad a colour change takes
test for the presence of heme in the urine and detects as few as 1 to 2 RBCs
per high power field.
one circumstance where false negative tests for hematuria occur. Some
manufactures make test strips that can oxidize ascorbic acid to reduce false
positive due to the heme in free urinary hemoglobin or myoglobin.
needs to be confirmed by microscopic analysis of the urine.
‘dipstick’ test for blood/heme?
along with CK.
and is thus rapidly excreted in the urine and has a half-life of about 2 hours.
It is also rapidly metabolized to bilirubin so serum levels return to normal
within 8 hours.
ruled out by negative urinary myoglobin.
present in the urine for other reasons during rhabdomyolysis.
levels are above 1.5mg/dl but visible changes in urine colour only occur when
serum levels are above 100mg/dl. A clear urinary supernatant usually helps to distinguish myoglobinuria from hemoglobinuria (red supernatant) after centrifugation.
(orthotolidine) dipstick at concentrations of only 0.5 to 1 mg/dL.
was 10,000 to 25,000. 46% of this cohort had AKI. In another study that included only patients with a CK over 5000 AKI was present in 51%.
makes the diagnosis.
with a good history and physical exam and some basic ‘hemolysis’ lab tests. What
can you do while waiting for the lab results?
heme in the urine. In theory there will be no RBCs in the urine and the
supernatant will be red without a red cell pellet. However, there are caveats
to this, an old urine sample and rarely a very dilute urine sample (low specific
gravity – see Finnians post) may cause red cells present in the urine to
hemolyze. Urine microscopy should be done to look for presence or absence of RBCs.
(beeturia), rhubarb, senna or Acute intermittent porphyria.
dipstick tests will be positive for blood.
Hematuria present with proteinuria is suggestive
of a glomerular cause. Hematuria with proteinuria greater than 1+ is almost
never due to extra glomerular bleeding even when gross hematuria is present.
However, massive bleeding can cause proteinuria. Massive bleeding is more
likely to occur due to extra glomerular bleeding and the presence of clots and
very red or pink urine as opposed to Coca-Cola coloured urine indicates extra