Microscopy Exam I

What increases cast formation?

Acidic pH, increased solute concentration, urinary stasis and increased proteins

Causes casts to disintegrate

Alkaline urine and dilute urine

An increase in casts signifies

Kidney disease

Hyaline casts are increased due to

Exercise and dehydration

Are hyaline casts clinically significant?

No, usually natural reasons

Are waxy casts clinically significant?

Yes. They are associated with nephrotic syndromes

Are granular casts clinically significant?

Yes, they are significant because they

Are fatty casts clinically significant?

Yes, seen in renal diseases

RBC cast pathology

Glomerular disease

Renal Tubule Epithelial Cell Cast indicates

Tubule necrosis

These help crystals form

Concentration of solute, pH, cold temp/time, flow of urine

Uric acid crystals increased in

Gout and cytotoxic drugs

Are uric crystals clinically significant?

Yes, usually in gout and cytotoxic drugs (chemo)

Calcium oxalate increased in

Ingestion of antifreeze, kidney stones, ingestion of certain foods (vit C)

Cystine crystals form in and dissolve in

pH less than 8.0, ammonia

Are cystine crystal significant?

Yes, congenital overflow, poor reabsorption, or damage to tubules

Are tyrosine crystals significant?

Yes, congenital overflow

Are leucine crystals significant?

Yes, congenital overflow or liver issues

Are cholesterol crystals significant

Yes, excessive tissue breakdown, renal disease, lymphatic rupture

Radiographic dye affecting specific gravity

Very high >1.035

Are calcium phosphates significant?

Yes, seen in kidney stones

Nephron function

Absorption, secretion, and concentration

Glomerulus function

Filters large proteins out of plasma (Filtration)

Proximal convoluted tubule function

Absorption

Loop of Henle function

Osmotic gradient

Distal convoluted tubule function

Reabsorption, concentrate urine(hydration needs of the body)

Collecting ducts function

Delivers to renal pelvis, last chance to absorb

Mesangium function

Controls blood flow, stabilizes capillary tuft, prevents clogging of the filtration barrier

Capillary endothelial cells function

Line the arterioles, large pores allow bigger proteins to filter quickly

Glomerular Basement Membrane (GBM) function

Shield of negativity prevents anything bigger than albumin from passing

Podocytes (foot cells) function

Zig-zag channel that phagocytize macromolecules too large to pass

What does the proximal convoluted tubule do with the ultrafiltrate?

Reabsorbed materials through active/passive transport

What do the loops of Henle do with the ultrafiltrate?

Dilutes the highly concentrated filtrate through active transport

Glucose maximal reabsorptive capacity

160-180mg/dL

What formed elements would you see in a nephritic syndrome?

Blood, red cell casts, other casts, waxy/broad possible if chronic

What formed elements would you see in a nephrotic syndrome?

Lipids, oval fat bodies, fatty casts

What physical sign is associated with a nephritic syndrome?

Hypertension

What physical sign is associated with a nephrotic syndrome?

Edema (swelling)

Acute Poststreptococcal Glomerulonephritis correlations

Edema around eyes, fatigue, sudden oliguria, hematuria, and sterile leukocyturia

Sterile leukocyturia definition

Seeing WBC casts even though an infection is not currently present

Rapid Progressive Glomerularonephritis NTK

Crescent shaped cells

Goodpasture Syndrome NTK

Anti-GBM

Goodpasture Syndrome can lead to what?

Rapidly Progressive Glomerulonephritis (RPGN)

First Morning specimen is ideal for

Nitrites and proteins, cytology, formed elements

Pre-determined length of time urine specimen collection advantages

Day to day variations, comprehensive look at kidney function

Midstream Clean Catch benefits

Gets rid of squamous epithelial cells and bacteria (specimen of choice for cultures and routine analysis)

Specimen labeling

Patient name, ID #, date/time of collection, type of specimen, collection technique, preservative used

Poor specimen handling can cause what to increase?

pH, nitrites

Poor specimen handling can cause what to decrease?

Bilirubin, glucose, nitrites, urobilinogen (things you’d need)

Amber/orange urine causes

Bilirubin, drugs, very concentrated

Brown urine causes

Excessive bilirubin, alkaptonuria

Green/Blue urine causes

Biliverdin, jaundice, drugs

Normal urine SG

1\.002-1.035

SG of plasma

1\.010

Why is a SG of 1.010 in urine significant?

Kidneys are not filtering plasma at all, complete loss of kidney function

Osmolality is only affected by

The number of solutes

Normal urine pH range

4\.5-8.0

pH higher than 8.5 indicates

Poor sample

White blood cell test tests for

Esterase-granulocytic leukocytes, presence of infection

Nitrites significant in

UTIs

Protein (albumin) is an important indicator for

Renal disease

Why might you see ketones in urine?

Metabolic abnormalities

Only bilirubin present in urine

Bile duct obstruction

Only urobilinogen present in urine

Increased cell lysis

Both bilirubin and urobilinogen present in urine

Liver disease

Ascorbic acid interferes with these tests

Blood, WBC, nitrite, glucose, bilirubin (false neg)

RBC pos chem/neg micro

Blood present in any capacity (HGB)

RBC neg chem/pos micro

False neg with ascorbic acid, mis ID with yeast,bubbles

RBC clinical significance

IV hemolysis, STD, inflammation, renal disease, injury

WBCs present cause

Infections, mucous build up

WBC pos chem/neg micro

WBC lysis

WBC neg chem/pos micro

False neg ascorbic acid (AA), mis ID, low #

WBC clinical significance

Inflammation, pyuria (pus), most renal diseases

Squamous epithelial cells

Most common cell, least clinically significant

Transitional Epithelial cells

Lower urinary tract, bladder health

Casts, proteins, and WBCs are seen in what type of UT infection?

Upper/kidney

WBCs, trace amounts of protein, and no casts are seen in what type of UT infection?

Lower/bladder

Membranous Glomerulonephritis (MGN) NTK

Large protein and hematuria, weight gain, edema, increased BP, nephrotic syndrome in adults

Membranous Glomerulonephritis (MGN) caused by

Thickening of the GBM, immune deposits

Focal Segmental Glomerulonephritis (FSG) causes

Scar tissue buildup in glomeruli

Membranoproliferative Glomerulonephritis (MPGN) correlations

Mental issues, azotemia, increased BP, small urine output

Minimal change disease (MCD) cause

Loose podocytes, T cell related, most common in children

Minimal change disease (MCD) correlations

Proteinuria, no hematuria, no hypertension

Alport Syndrome need to know

Increased transplant rejection due to rejecting collagen

IgA nephropathy NTK

Chronic glomerulonephritis, mucous membranes

IgA nephropathy causes

Systemic excess of IgA

Chronic glomerulonephritis complications

Glomeruli are hyalinized, tubule atrophy, dialysis or transplant likely, progressive destruction of glomeruli

Diabetic nephropathy NTK

Kidney blood vessels damaged, vascular sclerosis, leading cause of ESRD

Acute tubular necrosis correlations

Positive blood, low SG, WBC’s, Increased RTEs, various casts

Fanconi’s syndrome

Generalized loss of proximal tubule function

Nephrogenic Diabetes Insipidus

Releasing large amounts of dilute urine, excessive thirst, increase plasma osmolarity

Renal Tubular Acidosis (RTA) NTK

Tubules cant secrete H+ or absorb bicarb

Lower UTI symptoms

Pain when urinating, increase in voids, light lower abdominal pain

Urine analysis for Lower UTI

WBCs, bacteria, nitrite, possible protein, blood, transitional epis

Acute pyelonephritis NTK

Reflux, obstructions, hematogenous infection, ascending infection from lower, upper kidney infection

AP/ upper UTI correlations

Bacteria, WBCs, nitrite, casts, protein and blood variable, RTE, transitional, Low SG, significant flank pain

Chronic pyelonephritis causes

Untreated infections, chronic obstruction, renal calyces dilated and deformed

Acute Interstitial Nephritis NTK

Hematuria, mild proteinuria, sterile leukocyturia, eos, WBC casts, Drug or toxin abuse, allergic

Acute Renal Failure sign

Sudden drop in GFR, (cant remove waste, azotemia, and oliguria)

Chronic renal failure correlations

SG of 1.010, chronic proteinuria, hemoglobinuria, waxy and broad casts, azotemia, hypertension