M2: Microscopic Examination (Part 1: Macroscopic Screening) Flashcards
recommends that microscopic examination be performed
when:
- requested by a physician
- when a laboratory specified patient population is being tested
- when any abnormal physical or chemical result is obtained
Clinical and Laboratory Standards Institute (CLSI)
The purpose of the microscopic examination of the urinary
sediment is?
- detect and to identify insoluble materials present in the urine
These all contribute formed elements to the urine
4
- Blood
- Kidney
- Lower genitourinary tract
- External contamination
Some components are of no clinical significance and are considered normal unless they are present in increased amounts, what two factors must be consdered in examination of urinary sediment?
Identification and quantification of elements
Abnormalities in the physical and chemical portions of the urinalysis play a primary role in the decision to perform a microscopic analysis, thus the use of the term?
Macroscopic screening
MACROSCOPIC SCREENING AND MICROSCOPIC CORRELATIONS
Parameters considered significant vary among laboratories?
- Color
- Clarity
- Blood
- Protein
- Nitrite
- Leukocyte esterase
- Glucose (possibly)
MACROSCOPIC SCREENING AND MICROSCOPIC CORRELATIONS
Identify the screening test for the following possible microscopic findings:
RBC (blood)
Color (red), cloudy
or turbid
MACROSCOPIC SCREENING AND MICROSCOPIC CORRELATIONS
Identify the screening test for the following possible microscopic findings:
Squamous EC, WBC (confirm pathologic or non-patholpgic cause of turbidity)
Clarity: Cloudy or Turbid
MACROSCOPIC SCREENING AND MICROSCOPIC CORRELATIONS
Identify the screening test for the following possible microscopic findings:
Radiographic contrast media (X-ray dye)
Specific gravity >1.040
MACROSCOPIC SCREENING AND MICROSCOPIC CORRELATIONS
Identify the screening test for the following possible microscopic findings:
RBCs, RBC casts
Blood
MACROSCOPIC SCREENING AND MICROSCOPIC CORRELATIONS
Identify the screening test for the following possible microscopic findings:
Yeast
Glucose
MACROSCOPIC SCREENING AND MICROSCOPIC CORRELATIONS
Identify the screening test for the following possible microscopic findings:
WBCs intact or lysed, WBC casts (bacteria in UTI)
Leukocyte esterase positive
MACROSCOPIC SCREENING AND MICROSCOPIC CORRELATIONS
Identify the screening test for the following possible microscopic findings:
Bacteria (WBCs in UTI)
Nitrite positive
MACROSCOPIC SCREENING AND MICROSCOPIC CORRELATIONS
Identify the screening test for the following possible microscopic findings:
Increased casts and cells
Protein positive
SPECIMEN PREPARATION
T or F
Specimens should be examined while fresh or properly preserved.
T
SPECIMEN PREPARATION
These formed elements disintegrate rapidly, particularly in dilute alkaline
urine
RBCs, WBCs, and hyaline
casts
SPECIMEN PREPARATION
What concentration of urine does RBCs, WBCs, Hyaline casts disintegrate rapidly?
Dilute alkaline urine
high ph
SPECIMEN PREPARATION
You bring specimen to what temperature before centrifugation?
Room temperature
SPECIMEN PREPARATION
This temperature may cause precipitation of amorphous urates and phosphates and other non-pathologic crystals that can obscure other elements in the urine sediment.
Refrigeration
SPECIMEN PREPARATION
This temperature may dissolve some of these crystals
Warming specimen to 37 c
prior to centrifuging
SPECIMEN PREPARATION
This method of collection minimizes external contamination of the sediment
Midstream clean-catch specimen
SPECIMEN PREPARATION
Dilute random specimens cause what results?
False-negative
SPECIMEN PREPARATION
T or F
Shake specimen vigorously before transferring into a centrifuge tube
F (MIX specimen well before transferring into a centrifuge tube)
SPECIMEN VOLUME
What is the standard amount of urine that is usually centrifuged in a conical tube?
between 10 and 15 mL
SPECIMEN VOLUME
A standard amount of urine, usually between 10 and 15 mL,
is centrifuged in a ?
Conical tube
SPECIMEN VOLUME
This range of specimen volume provides an adequate volume from which to obtain representative sample of the elements present in the specimen.
10-15 mL of specimen volume
SPECIMEN VOLUME
This specific specimen volume is frequently used ecause
multiparameter reagent strips are easily immersed in
this volume and capped centrifuge tubes are often
calibrated to this volume
12-mL volume
SPECIMEN VOLUME
Familiarize the reason why 12mL of specimen volume is frequently used
- multiparameter reagent strips are easily immersed in this volume
- capped centrifuge tubes are often
calibrated to this volume
SPECIMEN VOLUME
T or F
If obtaining a 12-mL specimen is not possible, as with
pediatric patients, the volume of the specimen used
should be noted on just the medtech’s mind
F (should be reported on report form)
allows the physician to correct the results, if indicated
SPECIMEN VOLUME
T or F
If obtaining a 12-mL specimen is not possible, some laboratories make correction prior reporting
T
SPECIMEN VOLUME
For example, if 6-mL of urine was collected and centrifuged, the results are multiplied by what number ?
2
para maging 12 ata
CENTRIFUGATION
Centrifugation time?
5 minutes
CENTRIFUGATION
Speed of centrifugation?
RCF
400 relative centrifugal force (RCF)
CENTRIFUGATION
Speed of centrifugation?
RPM
1,500-2,500 RPM
CENTRIFUGATION
This RCF and RPM produces an optimum amount of sediment with the least chance of damaging the elements.
RCF: 400 RCF
RPM: 1,500-2,000 RPM
CENTRIFUGATION
To correct for differences in the diameter of centrifuge heads, what is the unit of centrifugation speed preferred to use?
Relatice Centrifugal Force (RCF)
than Revolutions per Minute (RPM)
CENTRIFUGATION
RPM value shown on centrifige tachometer can be converted to RCF using nomoframs available in many laboratory manuals or by using what formula?
RCF = 1.118 x 10^-5 x radius in cm x RPM ^2
CENTRIFUGATION
Using this will give a false negative result
Brake (braking)
CENTRIFUGATION
To prevent biohazardous aerosols, all speciments must be?
centrifuged in capped tubes
SEDIMENT PREPARATION
Volume of liquid that should remain in tube after decantation?
0.5-1.0 mL
SEDIMENT PREPARATION
T or F
In decantation, vigorously tap repeatedly the lower part of the tube with the finger to mix the sediment
F (gently tap repeatedly the lower part of the tube with the finger to mix the sediment)
Concentration factor formula?
CF = V of urine centrifuged / Sediment Volume
C = V/S