LEC 1 - INTRODUCTION TO CLINICAL MICROSCOPY

What did the early Color Charts describe?

The significance of 20 different urine colors to aid physicians

Who discovered Albuminuria?

Frederick Dekker

How did Frederick Dekker discover Albuminuria?

By boiling the urine

Who is Richard Bright?

The physician who emphasized the importance of urinalysis in routine patient examination

Why is Urinalysis performed?

It aids in the diagnosis of disease and helps monitor body function

How is urine formed?

It is an ultrafiltrate of plasma

What is the approximate amount of plasma filtered daily?

170,000 mL

What percentage of urine is water?

95% water

What percentage of urine is solute?

5% solute

What is the major metabolic waste product in urine?

Urea

Where is Urea produced?

In the liver from the breakdown of proteins and amino acids

What is the major inorganic solid dissolved in the urine?

Chloride

What is the average daily urine output?

1200 mL to 1500 mL

What is Oliguria?

A decrease in urine output

What is a main cause of Oliguria?

The body entering a state of dehydration

What is Anuria?

The cessation (complete stopping) of urine flow

What is Nocturia?

An increase in nocturnal (nighttime) excretion of urine

How does nocturnal urine output normally compare to daytime output?

Kidneys normally excrete two or three times more urine during the day than during the night

What is Polyuria?

Increased daily urine volume

What volume defines Polyuria in adults?

Approximately greater than 2.5 L per day

Diabetes Mellitus (DM) results from a defect in what two areas related to insulin?

Defect in pancreatic production of insulin or in the function of insulin itself

In DM, why does excess glucose get excreted in the urine?

The kidneys cannot reabsorb the excess glucose that results from increased body glucose formation

Why do patients with Diabetes Mellitus experience Polyuria?

To remove the excess glucose, the kidney must excrete increased amounts of water to necessitate the glucose's removal

What is the appearance of the urine in Diabetes Mellitus (DM), and why is the specific gravity high?

The urine is Dilute (light yellow/water-like) but has high specific gravity because of the increased glucose content

Diabetes Insipidus (DI) results from a decrease in the production or function of what hormone?

Antidiuretic Hormone (ADH)

In DI, why is water not reabsorbed, leading to Polyuria?

The lack of ADH means the water necessary for adequate body hydration is not reabsorbed from the plasma filtrate

How does the urine of patients with Diabetes Insipidus differ from Diabetes Mellitus urine in terms of dilution and specific gravity?

DI urine is truly dilute (lacks solutes) and has a low specific gravity

What is Polydipsia?

An intense/excessive sense of thirst

Why does Polydipsia occur in both Diabetes Mellitus and Diabetes Insipidus?

It is a compensatory mechanism for the excessive fluid loss (Polyuria) caused by the diseases

Which specimen is collected immediately upon waking and retained in the bladder for approximately 8 hours?

The First Morning Specimen

What is the primary benefit of using a First Morning Specimen?

It is the most concentrated and ideal for routine screening tests

Which is the most commonly received urine specimen?

The Random Specimen

What is the primary use of a Random Specimen?

Useful for routine screening tests to detect obvious abnormalities

What is the primary purpose of a 24-hour (or 12-hour) Timed Collection?

It is ideal for quantitative urine assays

What is the key collection requirement for a 24-hour urine specimen to be valid?

Collection must begin and end with an empty bladder

Which specimen is the 2nd voided specimen after fasting, and what is it used for?

The Fasting Specimen, used for glucose monitoring

How is the 2-Hour Post Prandial Specimen collected?

The patient voids before eating, and the specimen is collected 2 hours after consuming a routine meal

What analytes are tested in the urine during the Glucose Tolerance Test (GTT)?

Glucose and ketones

Which collection procedure is used for the Prostatic Specimen, and what does it determine?

It uses the three-glass collection procedure to determine prostatic infection

Which collection technique requires no patient preparation?

The Routine Void

Which technique is ideal for both bacterial culture and routine urinalysis because it minimizes contamination?

The Midstream Clean-Catch Specimen

What collection technique involves the external introduction of a needle through the abdomen directly into the bladder?

Suprapubic Aspiration

What are the two types of Catheterized Specimens mentioned?

Urethral and Ureteral

How is a Urethral Catheterized Specimen collected?

The catheter is inserted into the bladder via the urethra

How is a Ureteral Catheterized Specimen collected?

Same collection procedure as urethral, but urine is collected directly from the left or the right ureters

Which analyte changes due to oxidation or reduction of metabolites?

Color (Modified/Darkened)

Which analyte changes due to bacterial multiplication or breakdown of urea to ammonia?

Odor (Increased)

Which analyte changes due to breakdown of urea to ammonia by urease-producing bacteria/loss of CO2​?

pH (Increased)

Which analyte changes due to multiplication of nitrate reducing bacteria?

Nitrite (Increased)

Which analyte changes due to multiplication?

Bacteria (Increased)

Which analyte changes due to bacterial growth and precipitation of amorphous material?

Clarity (Decreased)

Which analyte changes due to glycolysis and bacterial use?

Glucose (Decreased)

Which analyte changes due to volatilization and bacterial metabolism?

Ketones (Decreased)

Which analyte changes due to exposure to light / photo oxidation to biliverdin?

Bilirubin (Decreased)

Which analyte changes due to oxidation to urobilin?

Urobilinogen (Decreased)

Which analyte changes due to disintegration in dilute alkaline urine?

RBCs, WBCs, and Casts (Decreased)