[Histonet] Re: urine hemosiderin

[Bob Richmond]

Urine hemosiderin is an archaic procedure that still may be in the
handy-dandy intern's guide, along with serum haptoglobin, as part of
working up a suspected transfusion reaction. An order for either of these
tests needs to be promptly reviewed to see if a doctor is trying to do an
amateur transfusion reaction workup. That's a bit of an emergency.

About thirty years ago I wrote this procedure, on two different occasions.
I've appended both of them.

Bob Richmond
Samurai Pathologist
Maryville TN
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URINE HEMOSIDERIN

PRINCIPLE: The iron-containing pigment hemosiderin is found in the urine,
either free or within casts and epithelial cells, in diseases in which this
pigment is lost through the kidneys. Hemosiderin may be seen on direct
examination of urine sediment, and its presence confirmed with the Perls
reaction for stainable iron.

SPECIMEN: A random urine specimen with the sediment in good condition for
examination is required. Do not perform the test unless a suitable specimen
is available. Urine hemosiderin is not a stat procedure, and is not part of
the routine work-up of a suspected transfusion reaction.

REAGENTS:
    2% solution of potassium ferrocyanide in distilled water
    1% solution of concentrated hydrochloric acid in distilled water

EQUIPMENT:
    The same equipment is required as for routine examination of urinary
sediment. Be sure that all materials are clean, since the iron stain reacts
with many contaminant materials in the environment.

PROCEDURE:
    1. Prepare centrifuged urinary sediment in the usual fashion.
    2. Examine the sediment for hemosiderin granules. These are
yellow-brown granules which may be free in the sediment, or may be inside
of epithelial cells or casts. The granules are brilliantly refractile; that
is, they “light up” when you rack the condenser of the microscope down.
    3. Add to the rest of the sediment in the tube:
        5 mL of 2% potassium ferrocyanide
        5 mL of 1% hydrochloric acid
    4. let stand 10 minutes
    5. centrifuge
    6. examine under the microscope

RESULTS:
    Hemosiderin appears as bright blue granules of ferric ferrocyanide
after staining. No such material is present in normal urine. Unfortunately
no satisfactory positive control is available. Review the material with the
pathologist if you are uncertain of your results. Report as urine
hemosiderin: negative OR positive.

REFERENCES:
    1. Rous, P. Urinary siderosis. J Exper Med 1918; 28:645. This very old
article contains the original method, cited in Todd-Sanford and other
modern works.
    2. Bradley M, Schumann GB, Ward CJW: Examination of urine,
Todd-Sanford-Davidsohn Clinical Diagnosis and Management by Laboratory
Methods. 16th edition. Edited by JB Henry. Philadelphia, Saunders Company,
1979, p 630.

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URINE HEMOSIDERIN

PRINCIPLE: Hemosiderin may appear in renal tubule cells as a result of
excessive iron storage, or two to three days after an acute hemolytic
episode. Hemosiderin granules may as a result appear in the urine. This
test is usually ordered in suspected hemolytic transfusion reaction, though
it is not of much diagnostic value in this situation.

PATIENT PREPARATION: none

SPECIMEN: Any fresh urine specimen may be tested.

REAGENTS:
2% potassium ferrocyanide (wt/vol), prepared fresh, measurements
approximate
1% (vol/vol) hydrochloric acid

DIRECTIONS:
1. Prepare sediment from at least 10 mL of urine.
2. Examine the sediment under the microscope in the usual fashion. Look for
coarse golden-brown highly refractile granules, preferably within
epithelial cells or casts. You may need the help of the pathologist to do
this. If no hemosiderin granules are found, do not proceed with the test,
and report “no urine hemosiderin identified”.
3. If hemosiderin granules are seen, confirm their identity by suspending
the sediment in a fresh mixture of equal parts of potassium ferrocyanide
and hydrochloric acid. Allow it to stand for 10 to 30 minutes.
4. Centrifuge, and examine the sediment again. The hemosiderin granules
should now appear dark blue. Foreign matter often stains blue, and can
cause false positive interpretations. Once again, you may need the help of
the pathologist.
5. If hemosiderin granules are definitely identified, report “urine
hemosiderin present”.

CONTROLS: Run a clean normal urine as a negative control. There is no
satisfactory positive control available. A patient with hemochromatosis
(they’re often subjected to repeated therapeutic phlebotomy) may have
hemosiderinuria.

REFERENCES:
1. Rous, P. Urinary siderosis. J. Exper Med 28: 645, 1918. This ancient
article is cited in successive editions of Todd-Sanford (now John B. Henry).

AUTHOR: Robert S. Richmond, M.D., F.C.A.P.