Bence Jones Protein Detection Methods

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Questions and Answers

What role does protein electrophoresis play in the detection of Bence Jones protein?

Protein electrophoresis is used to identify the presence of Bence Jones protein by showing a distinct peak in the globulin region.

How does the traditional electrophoretic procedure differ from newer methods in detecting Bence Jones protein?

The traditional method uses Amido black stain on a 200-fold concentrated urine sample, whereas newer methods utilize modified Coomassie brilliant blue stain on less concentrated urine.

At what temperature does Bence Jones protein precipitate, and what is its behavior upon heating?

Bence Jones protein precipitates at temperatures between 40°C and 60°C and redissolves near 100°C.

What are alternative methods for detecting Bence Jones protein aside from electrophoresis?

Alternative methods include immunofixation electrophoresis and immunoassay for free light chains. Signup and view all the answers

In cases of significant Bence Jones proteinuria, what is the expected result across detection methods?

Most methods would show positive results in cases of significant Bence Jones proteinuria. Signup and view all the answers

What is the principle underlying the reagent strip method for detecting hemoglobin or myoglobin?

The test detects the pseudoperoxidase activity of hemoglobin or myoglobin that reacts with hydrogen peroxide and chromogen to form an oxidized chromogen and water. Signup and view all the answers

Describe the visual result on the reagent strip that indicates a positive test for hemoglobin or myoglobin.

A positive test shows a speckled pattern for low RBC numbers or a uniform color for free hemoglobin or high RBC counts. Signup and view all the answers

Identify two potential substances that may cause false positive results in the reagent strip test.

Vegetable peroxidase and Escherichia coli peroxidase may cause false positives. Signup and view all the answers

List two factors that could lead to false negative results in the reagent strip method.

High levels of ascorbic acid and the presence of nitrites can result in false negatives. Signup and view all the answers

Explain the importance of detecting hemoglobin or myoglobin in urine.

Detecting hemoglobin or myoglobin in urine can indicate possible hematuria or muscle damage, respectively. Signup and view all the answers

What is hemosiderin, and how is it formed in the kidneys after a hemolytic episode?

Hemosiderin is an iron-storage complex formed from the catabolism of hemoglobin by proximal tubular cells in the kidneys after an acute hemolytic episode. Signup and view all the answers

Why might the reagent strip method for hemoglobin be negative despite the presence of hemosiderin in urine?

The reagent strip for hemoglobin can be negative because hemosiderin is typically present 2-3 days post-hemolysis, after free hemoglobin has been filtered and cleared. Signup and view all the answers

In what type of diseases might hemosiderin appear in the urine sediment besides acute hemolysis?

Hemosiderin can appear in the urine sediment in diseases characterized by true siderosis of kidney parenchyma, such as hemochromatosis. Signup and view all the answers

What conclusion can be drawn from the presence of hemosiderin in urine regarding hemolysis?

The presence of hemosiderin in urine indicates a chronic hemolytic state, though its detection is rarely required for diagnosing hemolysis. Signup and view all the answers

Identify the cellular forms in which hemosiderin can be found within the urine.

Hemosiderin can be found as free yellow-brown granules or located in epithelial cells and occasionally in casts within the urine. Signup and view all the answers

What does the presence of hemoglobinuria indicate about the type of hemolysis occurring?

It indicates significant intravascular hemolysis. Signup and view all the answers

What happens to free hemoglobin when it binds to plasma haptoglobin under normal conditions?

It is transported in the blood and prevents free hemoglobin from passing into the urine. Signup and view all the answers

Which modification occurs to hemoglobin when its binding capacity to haptoglobin is saturated?

The excess hemoglobin passes through the glomerulus as αβ dimers. Signup and view all the answers

What role do proximal tubular cells play in the fate of hemoglobin after filtration?

They reabsorb some of the hemoglobin for further processing. Signup and view all the answers

How can strenuous exercise lead to hemoglobinuria?

It can cause direct trauma to small blood vessels, leading to hemolysis and hemoglobinuria. Signup and view all the answers

What physiological condition primarily leads to myoglobinuria?

Rhabdomyolysis, which involves the acute destruction of muscle fibers, primarily leads to myoglobinuria. Signup and view all the answers

How does the removal rate of free myoglobin compare to that of the hemoglobin-haptoglobin complex?

Free myoglobin is excreted quickly, while the hemoglobin-haptoglobin complex is removed more slowly. Signup and view all the answers

Identify one activity that can frequently cause myoglobinuria and explain why.

Strenuous exercise, such as marathons, can cause myoglobinuria due to the intense muscle strain leading to muscle fiber damage. Signup and view all the answers

Name two less common causes of myoglobinuria besides rhabdomyolysis.

Dermatomyositis and defects in muscle phosphofructokinase are two less common causes of myoglobinuria. Signup and view all the answers

What is the molecular weight of free myoglobin, and why is this relevant?

The molecular weight of free myoglobin is 17,000, which is relevant as it affects its rapid excretion in urine. Signup and view all the answers

What is the main purpose of the Acetest?

To detect ketones in urine. Signup and view all the answers

Explain the enzymatic method used for detecting beta-hydroxybutyric acid.

It uses beta-hydroxybutyrate dehydrogenase to detect the acid. Signup and view all the answers

What differentiates hematuria from hemoglobinuria?

Hematuria refers to blood cells in urine, while hemoglobinuria refers to free hemoglobin in urine. Signup and view all the answers

What is the relative frequency of hematuria compared to myoglobinuria?

Hematuria is common, while myoglobinuria is rare. Signup and view all the answers

What significance does microscopic hematuria have in a screening population?

It can be detected in up to 16% of screening populations using dipstick tests. Signup and view all the answers

What are the three intermediate products of fatty acid metabolism known as ketones?

Acetone, acetoacetic acid, and beta-hydroxybutyric acid. Signup and view all the answers

Under what condition do ketones appear in urine?

Ketones appear in urine when fat reserves are needed for energy. Signup and view all the answers

What does the presence of ketonuria indicate about a patient's metabolic state?

Ketonuria indicates the presence of ketoacidosis and may signal impending coma. Signup and view all the answers

What is the clinical significance of ketone testing in patients with uncontrolled diabetes mellitus?

It helps monitor insulin dosage, detect electrolyte imbalances, and assess excessive carbohydrate loss. Signup and view all the answers

What is the maximum amount of acetoacetic acid that may be present in urine without clinical evidence of ketosis?

Up to 50 mg of acetoacetic acid per deciliter. Signup and view all the answers

Name two conditions associated with renal tubular dysfunction mentioned in the content.

Fanconi's syndrome and Galactosemia. Signup and view all the answers

Which method is primarily used for ketone testing and what does it measure?

Reagent strips using sodium nitroprusside measure acetoacetic acid and with glycine also measures acetone. Signup and view all the answers

What are the common causes of false positive results in ketone testing?

Pigmented urine and the presence of dyes or phenylketones can lead to false positives. Signup and view all the answers

Identify a reason for false negative results in ketone testing.

Bacterial breakdown of acetoacetic acid can lead to false negatives. Signup and view all the answers

Why are Type 1 diabetic patients more prone to ketosis?

They are more susceptible due to insulin management issues often exacerbated by infection or stress. Signup and view all the answers

List two diseases that can cause hematuria and briefly explain their impact on the kidneys.

Membranous nephropathy and IgA nephropathy can cause hematuria, leading to kidney damage and impaired function. Signup and view all the answers

What percentage of patients in the study showed normal histology despite presenting with hematuria?

More than 15% of patients showed normal histology. Signup and view all the answers

Describe how trauma might lead to hematuria.

Trauma can cause hematuria by direct injury to the kidneys or urinary tract, such as from kidney stones. Signup and view all the answers

Identify a rare condition that has been reported to present with hematuria and describe the additional symptom.

Giant cell arteritis has been reported to present with hematuria and fever. Signup and view all the answers

How can vigorous exercise lead to hematuria in healthy individuals?

Strenuous exercise, such as marathon running, can cause hematuria due to stress on the bladder mucosa. Signup and view all the answers

What is glycosuria and what conditions can lead to its occurrence?

Glycosuria is the presence of glucose in the urine, which can occur due to various conditions such as burns, infections, fractures, and pregnancy. Signup and view all the answers

In pregnancy, how does glomerular filtration rate affect glucose reabsorption?

During pregnancy, an increased glomerular filtration rate can lead to glycosuria by causing filtered glucose to be inadequately reabsorbed. Signup and view all the answers

What does the presence of glycosuria without hyperglycemia indicate?

Glycosuria without hyperglycemia typically indicates renal tubular dysfunction and reduced glucose reabsorption. Signup and view all the answers

How can certain medications contribute to glycosuria?

Some medications, such as thiazides and corticosteroids, can lead to glycosuria by interfering with glucose metabolism or reabsorption. Signup and view all the answers

What is the significance of detecting persistent glycosuria during pregnancy?

Persistent glycosuria during pregnancy may indicate a risk for gestational diabetes and warrants further medical evaluation. Signup and view all the answers

Flashcards

Hemosiderin in Urine

A breakdown product of hemoglobin found in the urine, indicating a past hemolytic episode.

How does hemosiderin form in urine?

Red blood cells break down into hemoglobin which is then filtered by the kidneys. Hemoglobin is further processed into ferritin and hemosiderin within the kidney cells.

When does hemosiderin appear in urine?

Hemosiderin appears in the urine 2-3 days after a hemolytic episode, indicating a past hemolytic episode.