mycelia. Scrapings from the affected area of the skin
are mounted in 10% KOH for positive laboratory
To detect fungi in infected tissue using the KOH
preparation, follow the steps below.
1. Place skin, hair, or nail scrapings from the
affected area on a glass slide and add one drop of
10% KOH. (Dissolve 10 g of KOH in 100 ml of
2. Place a coverslip on the preparation.
3. Warm the preparation gently over a flame, being
careful not to boil it, and allow it to stand until
clear. Do not allow the preparation to dry out.
4. Examine the preparation by using the
high-power objective on microscope with
Fungi on the skin and nails appear as
refractile fragments of hyphae.
Fungi in the hair appear as dense clouds
around the hair stub or as linear rows inside
the hair shaft.
three types of urine specimens, the methods
used to preserve urine specimens, and the
procedure for performing a urinalysis.
Since the physical and chemical properties of
normal urine are constant, abnormalities are easily
detected. The use of simple tests provides the
physician with helpful information for the diagnosis
and management of many diseases.
This section deals with the three types of urine
specimens, methods used to preserve urine specimens,
the procedure for performing a routine and
microscopic examination of urine specimens, and
some of the simpler interpretations of the findings.
Urine specimens for routine examinations must be
collected in aseptically clean containers.
circumstances warrant, avoid catheterization because
it may cause a urinary tract infection. Specimens of
female patients are likely to be contaminated with
albumin and blood from menstrual discharge, or with
albumin and pus from vaginal discharge.
bacteriologic studies, care must be taken to ensure that
the external genitalia have been thoroughly cleansed
with soap and water. The patient must void the initial
stream of urine into the toilet or a suitable container
and the remainder directly into a sterile container. All
urine specimens should either be examined when
freshly voided, or refrigerated to prevent decom-
position of urinary constituents and to limit bacterial
growth. In the following sections, we will cover three
types of urine specimens: random, first morning, and
Random Urine Specimen
A random urine specimen is urine voided without
regard to the time of day or fasting state. This sample is
satisfactory for most routine urinalyses. It is the least
valid specimen, since test results may reflect a
particular meal or fluid intake.
First Morning Urine Specimen
The first morning urine specimen is the first urine
voided upon rising. It is the best sample for routine
urinalysis, because it is usually concentrated and more
likely to reveal abnormalities. If positive results are
obtained from the first morning specimen, the
physician may order a 24-hour specimen for
Twenty-Four Hour Urine Specimen
The 24-hour urine specimen measures the exact
output of urine over a 24-hour period.
following steps to collect this specimen.
1. Have patient empty bladder early in the morning
and record time. Discard this urine.
2. Collect all urine voided during next 24 hours.
3. Instruct patient to empty bladder at 0800 the
following day (end of 24-hour period). Add this
urine to pooled specimen.
Refrigerate specimen during collection, and,
depending on the test being performed, add a
preservative to the first specimen voided.
The normal daily urine volume for adults ranges
from 800 to 2000 ml, averaging about 1,500 ml. The
amount of urine excreted in 24 hours varies with fluid
intake and the amount of water lost through
perspiration, respiration, and bowel activity. Diarrhea