Clinical Chemistry Unit 6 - Non-Protein Nitrogens and Kidney Function

This hormone, which is secreted by the kidney, regulates RBC synthesis in the bone marrow.

erythropoietin

This hormone, which is secreted by the kidney, regulates the balance between water and sodium in the body and effects blood pressure.

renin

Name the six primary tasks performed by the kidney that were covered in this chapter.

fluid and electrolyte balance/excretion of waste products/secretion of hormones/excretion of drugs and toxins/urine formation/acid base balance

What are the four main areas of the kidney?

cortex/medulla/pelvis/ureter

What is the name of the functional unit of the kidney?

nephron

What are the five parts of the nephron?

glomerulus/proximal convoluted tubule/loop of Henle/distal convoluted tubule/collecting duct

The glomerulus is located within the ________ of the kidney.

cortex

This part of the kidney is known as a 'knot' of capillaries. It is responsible for filtering blood and preventing large particles from entering the proximal convoluted tubule.

glomerulus

The blood that is filtered through the glomerulus is known as the...

glomerular filtration rate (GFR)

The ________ artery brings blood to the glomerulus.

afferent

The ________ artery takes blood away from the glomerulus

efferent

This part of the nephron is responsible for reabsorbing valuable substances back into the blood.

proximal convoluted tubule

Term used to describe the maximum amount of a substance the kidney can reabsorb.

renal threshold

The loop of Henle is composed of the ________ and ________ loops.

ascending/descending

Which part of the loop of Henle is primarily responsible for water reabsorption?

descending loop

Which part of the loop of Henle is responsible for reabsorbing sodium and chloride?

ascending loop

The part of the nephron is mainly responsible for the reabsorption of water, sodium, and chloride.

loop of Henle

This part of the nephron makes small adjustments to the electrolyte and pH balance. it is regulated by the hormones Aldosterone and ADH.

distal convoluted tubule

This part of the nephron is the site for urine concentration and dilution. It drains urine into the ureter.

collecting duct

What are the three types of glomerular diseases?

acute glomerulonephritis/chronic glomerulonephritis/nephrotic syndrome

What are the three main causes of acute glomerulonephritis?

drug exposure/bacterial infections/autoimmune disorders (i.e. lupus, Goodpasture's syndrome)

What microorganism is commonly associated with acute glomerulonephritis?

BHSA (Group A Strep, Strep pyogenes)

Name some symptoms associated with acute glomerulonephritis:

weakness/fever/abdominal pain/malaise/edema/oliguria/hematuria/joint or muscle pain/rash

What is the best indicator of acute glomerulonephritis?

RBC casts

What eight laboratory findings are indicative of acute glomerulonephritis?

hematuria/proteinuria/decreased GFR/increased BUN/increased creatinine/sodium or water retention/hyaline and granular casts/RBC casts

This stage of glomerular disease occurs after prolonged inflammation of the glomerulus.

chronic glomerulonephritis

What four lab results are indicative of chronic glomerulonephritis?

decreases in renal function/slight proteinuria/slight hematuria/uremia (excess nitrogen in blood)

This glomerular disease occurs when there is an increase in permeability in the glomerulus. Often associated with diabetes mellitus.

nephrotic syndrome

What are some symptoms of nephrotic syndrome?

swelling (primarily in the hands, feet and eyes)

What lab results are indicative of nephrotic syndrome?

massive proteinuria/hypoabluminemia/lipiduria/high cholesterol

Tubular disease occurs in all renal diseases where ________ falls.

GFR

What are the two types of RTA (renal tubular acidosis)

distal RTA/proximal RTA

________ RTA occurs when the tubules can't keep up with the pH balance between the blood and the tubular fluid.

distal

________ RTA occurs when bicarbonate decreases, which results in hyperchloremic acidosis.

proximal

What four factors can contribute to acute inflammation in tubular disease?

analgesic drugs/radiation toxicity/renal transplant rejections/infections (viral, fungal, bacterial)

What five lab findings are associated with acute inflammation in tubular disease?

decreased GFR/decrease in concentrating ability (of urine)/metabolic acid excretion/WBC casts/problem with sodium balance

Term for urinary tract infection originating from the kidney.

pyelonephritis

Term for urinary tract infection originating from the bladder.

cystitis

What five lab findings are indicative of urinary tract infections?

bacteriuria/hematuria/pyuria/WBC casts/positive nitrate test

What are the three major causes of urinary obstruction?

tumors/congenital defects/kidney stones

Renal calculi is another name for...

kidney stones

Where do urinary blockages generally occur?

below the collecting duct (upper tract)/bladder (lower tract)

Kidney stones are associated with the saturation of these three insoluble substances.

calcium oxalate/uric acid/cystine

What are the three symptoms of urinary obstruction?

decreased concentrating ability/decreased GFR/slowness in voiding

What six tests can be used to diagnose a urinary obstruction?

UA (urinalysis)/culture/BUN/serum creatinine/CBC/radiological imaging (used to confirm presence of stones)

Acute renal failure is characterized by a GFR that is...

less than 10 mL/min

List the five examples of toxic abuse associated with acute renal failure discussed in class:

hemolytic transfusion reactions/heavy metal poisoning/antifreeze poisoning/analgesic poisoning/antibiotic toxicity

List the three examples of hypoxic abuse associated with acute renal failure discussed in class:

sepsis/burns/cardiac failure

List some (eight) symptoms of acute renal failure:

decreased urine output/water retention/edema/hypertension/decreased blood sodium/increased blood potassium/increased BUN/increased creatinine

The kidney will not see a change in BUN or creatinine until kidney function is below ________.

50%

What is the normal range for urine albumin?

4-25 mg/24 hours

What five tests can be used to test kidney function:

clearance tests/urinalyis/urine electrophoresis/myoglobin/non-protein nitrogens

This type of test measures substances in a timed specimen to determine how they are removed from the bloodstream.

clearance test

What are the four types of clearance tests?

creatinine clearance/GFR/inulin clearance/urea (BUN)

What is the most commonly used clearance test?

creatinine clearance

Amber blood suggests the presence of...

lysed blood

Red urine suggests the presence of...

blood

Green urine suggests the presence of...

pseudomonas

Brown urine suggests the presence of...

bilirubin

Orange urine suggests the presence of...

pyridium

What is the normal range for the SG of urine (specific gravity)

1.005-1.030

What is the normal range for urine pH?

4.5-8.0

Urine electrophoresis is useful in distinguishing between ________ and ________.

acute glomerular nephropathy/tubular proteinuria

This test is used to separate proteins in the urine.

urine electrophoresis

List seven substances found in microscopic UA that suggests renal failure.

RBCs (1-3/hpf)/WBC (1-3/hpf)/epithelial cell (1-3/hpf)/yeast/bacteria/crystals/casts

Casts form in the nephrons when ________ proteins are in the loop of Henle.

Tamm horsfall

________ is a small protein released from cardiac and smooth muscle.

myoglobin

BUN stands for...

blood urea nitrogen

What is the formula for calculating urea levels from BUN.

BUN X 2.14 = urea

Term used to describe nitrogen (urea) in the blood. Usually associated with early renal failure.

azotemia

Term used to describe urea in the blood. Usually associated with end stage renal failure.

uremia

What are the three categories of acute of acute kidney damage?

pre-renal/renal/post-renal

What is the leading cause of pre-renal failure?

CHF (congestive heart failure)

The pre-renal stage is characterized by a(n) ________ BUN, ________ creatinine, and a ________ BUN/creatinine ratio.

increased/normal/increased

The renal stage is characterized by a(n) ________ BUN, ________ creatinine, and a ________ BUN/creatinine ratio.

increased/increased/normal (same)

The post-renal stage is characterized by a(n) ________ BUN, ________ creatinine, and a ________ BUN/creatinine ratio.

normal/increased/decreased

What is the range for a normal BUN/creatinine ratio?

10:1 to 20:1

What four methods can be used to measure BUN?

colorimetric assays/coupled enzymatic assay/alternate coupled enzyme assay/pH electrode

What two methods can be used to measure urea?

colorimetric assays/coupled enzymatic assay

In a colorimetric assay for urea, look for the ________ or ________ reaction.

Nessler's/Berthelot

What is the name of the two enzymes used in the most common coupled enzymatic assay for urea?

urease/glutamate dehydrogenase

As an alternative coupled enzyme assay, what is the enzyme used?

peroxidase

What specimens can be used to test for urea?

plasma/serum/urine

Tubes containing these three substances must be avoided when collecting samples for urea testing.

ammonia/fluoride/citrate

What is the normal range for BUN?

7-18 mg/dl

Creatinine is made from..

creatine

Creatine is synthesized in the...

liver

Creatinine levels are proportional to...

muscle mass

Creatinine tests are usually performed over a time frame of...

24 hours

Name four conditions that can cause elevated levels of creatine:

muscular dystrophy/hyperthyroidism/trauma/cardiopathy

Who created the original method of measuring creatine?

Jaffe

Creatine was originally measured by adding ________.

picric acid

Who came up with the modern method of detecting creatine?

Folin/Wu

What is the name of the modern method of detecting creatine?

kinetic Jaffe

What is the normal range for serum creatine in adult men using the kinetic Jaffe method?

0.9-1.3 mg/dL

What is the normal range for 24 hour urine creatine in adult males?

800-2000 mg/24 hours

What is the formula used to calculate creatinine clearance?

(urine creatine/serum urea) X (volume (mL)/time (min)) X (1.73/SA (surface area))

Hour many minutes are in 24 hours?

1,440

What is the normal range for creatinine clearance rate for adult men?

97-137 mL/min

What is the normal range for serum creatine in adult men using the coupled enzymatic method?

0.6-1.1 mg/dL