STRASINGER (7TH ED. | CHAPTER 7: MICROSCOPIC EXAMINATION OF URINE) Flashcards
What is the third part of routine urinalysis?
Microscopic examination of urinary sediment
What is the purpose of microscopic examination of urine?
To detect and identify insoluble materials in the urine
To identify and quantitate the elements present
What are the (4) components that contribute formed elements in the urine?
- Blood
- Kidney
- Lower genitourinary tract (GUT)
- External contamination
What are the (11) formed elements in the urine?
- RBCs
- WBCs
- Epithelial cells
- Casts
- Bacteria
- Yeast
- Parasites
- Mucus
- Spermatozoa
- Crystals
- Artifacts
Are all elements in the urinary sediment clinically significant? Why or why not?
No, some of the components are not clinically significant, hence, they are considered normal not unless they are present in increased amounts, hence, identification and quantitation of urinary sediment must be done
Microscopic analysis is subject to what (4) procedural variations?
- The methods by which the sediment is prepared
- The volume of sediment actually examined
- The methods and equipment used to obtain visualization
- The manner in which results are reported
What is the significance of the given screening test?
Screening test = Color
Blood
What is the significance of the given screening test?
Screening test = Blood
RBCs, RBC casts
What is the significance of the given screening test?
Screening test = Clarity
Hematuria vs hemoglobinuria/myoglobinuria
Confirm pathological or nonpathological; cause of turbidity
What is the significance of the given screening test?
Screening test = Protein
Casts, cells
What is the significance of the given screening test?
Screening test = Nitrite
Bacteria, WBCs
What is the significance of the given screening test?
Screening test = Leukocyute esterase
WBCs, WBC casts, bacteria
What is the significance of the given screening test?
Screening test = Glucose
Yeast
What is the meaning of CLSI?
The Clinical and Laboratory Standards Institute
What are the (2) characteristics of urine specimens for microscopic examination?
- Fresh
- Adequately preserved
What are the (3) formed elements that disintegrate rapidly in dilute alkaline urine?
- RBCs
- WBCs
- Hyaline casts
What are the (3) formed elements that precipitate due to refrigeration?
- Amorphous urates
- Amorphous phosphates
- Nonpathological crystals
How to dissolve some of the crystals for them to not obscure other elements present in the urine?
Warm the urine specimen to 37DC before centrifuging
What is the method of collection to minimize external contamination of the sediment?
Clean-catch midstream
In terms of physical and chemical examination of urine, what type of specimen may cause false-negative readings?
Dilute random specimens
What should be done prior to decanting a portion of urine specimen to the centrifuge tube?
The specimen should be thoroughly mixed
What is the standard volume of urine for examination?
10 - 15 mL
What is the tube used for centrifuging urine?
Conical tube
What is the volume of urine that is frequently used for urinalysis? Why?
12 mL, because multiparameter reagent strips are easily immersed and capped centrifuge tubes are often calibrated to this volume
What should be done if collecting 12 mL urine specimen for urinalysis is not possible, like in the case of pediatric patients?
It should be noted on the report form
What should be the speed of centrifugation of urine for urinalysis?
400 RCF
