urine screening (metabolic disorders)

Question 1

• Tryptophan produces serotonin
• Serotonin from tryptophane is produced by the intestinal argentaffin cells and is carried in the body to the muscles by platelets
• Excess excreted in the urine as (?)
• Argentaffin cell tumors = ↑ ↑ (?) in urine from excess serotonin produced
• Nitrous acid and 1-nitroso-2-naphthol produce purple to black color
• Normal: 2-8 mg/day, >25 mg/day in disease
• Can perform test on random specimens
• No bananas, pineapples, tomatoes, phenothiazines, and acetanilids for 72 hours
• 24-hour urines must be preserved with HCl or boric acid

Answer 1

5-HIAA

Question 2

homogentistic acid test

• Addition of silver nitrate and ammonium hydroxide to urine
• black urine

Answer 2

Ammoniacal Silver Nitrate Test

Question 3

• skeletal structure is abnormal and there is severe mental retardation
• Bone marrow transplants and gene replacement therapy
• acid-albumin (turbidity after 30 mins)
• cetyltrimethylammonium bromide (CTAB) turbidity tests (turbidity after 5 mins)
• Metachromatic staining (blue spot)

Answer 3

hunter syndrome

Question 4

• p-hydroxyphenylpyruvic acid dioxygenase
• result in mental retardation if dietary restrictions of phenylalanine and tyrosine are not implemented

Answer 4

type 3 tyrosinemia

Question 5

one of Garrod’s original six IEMs

Answer 5

pentosuria

Question 6

• port wine color after air exposure, also seen on
  diapers
  §Ehrlich reaction: only for ALA and porphobilinogen
• Convert ALA to porphobilinogen by adding acetyl acetone
• Fluorescence under ultraviolet light used for other porphyrins; extract into glacial acetic acid and ethyl acetate; does not distinguish
• Violet, pink, red, based on concentration

Answer 6

porphyrin disorders

Question 7

• Enzyme deficiency is homogentisic acid oxidase
• Black alkaline urine, possible black-stained diapers
• Manifests later in life with brown pigment deposits in tissues
• blue with ferric chloride
• yellow precipitate with clinitest
• black with silver nitrate and ammonium hydroxide

Answer 7

alkaptonuria

Question 8

• tyrosine aminotransferase
• Persons develop corneal erosion and lesions on the palms, fingers, and soles of the feet believed to be caused by crystallization of tyrosine in the cells

Answer 8

type 2 tyrosinemia

Question 9

• Current state-mandated screening for as many as 29 inborn errors of metabolism
• Urine tests are primarily for follow-up
• Disorders can cause abnormal urinalysis results
• Heel stick blood tests are used for testing
• Performed before infant leaves hospital
• Metabolites appear first in the blood
• Analyze by tandem mass spectrophotometry, MS/MS
• Gene testing is being worked on

Answer 9

newborn screening

Question 10

melanuria

• oxidation of chromogen
• gray or black ppt

Answer 10

ferric chloride tube test

Question 11

• Fumarylacetoacetate hydrolase (FAH)
• Produces a generalized renal tubular disorder and progressive liver failure in infants soon after birth

Answer 11

type 1 tyrosenemia

Question 12

• Breakdown in a normal metabolic pathway causing accumulation of previous metabolite
• Overrides Tm or is not normally reabsorbed
• Inherited lack of specific enzyme for protein,fat, or carbohydrate metabolism–Inborn Error of Metabolism

Answer 12

overflow

Question 13

• Differentiation of urobilinogen, porphobilinogen and other Ehrlich-Reactive Compounds.
• Extraction with CHLOROFORM and BUTANOL

Answer 13

watson-schwartz test

Question 14

• 1 in 10,000 births
• Autosomal-recessive; heterozygotes normal
• Damage to child’s mental capacity
• Alternate pathways as child matures
• Avoid ↑ phenylalanine foods (aspartame)
• Urine and 5% ferric chloride produces a permanent green-blue color

Answer 14

phenylketonuria

Question 15

• immediate precursor to methylmalonic acid
• errors in the metabolic pathway converting isoleucine, valine, threonine, and methionine to succinyl coenzyme A

Answer 15

propionic acidemia

Question 16

• crystalline deposits of cystine in many areas of the body
• defect in the lysosomal membranes
• Positive test results for reducing substances

Answer 16

cystinosis

Question 17

amino acid disorders (aminoacidurias)

Answer 17

• Phenylketonuria,
• tyrosyluria,
• alkaptonuria

Question 18

• Inborn error of metabolism, autosomal-recessive
• 1-week failure to thrive is noticed
• Urine: strong odor of maple syrup, and thick, dark appearance
• Dietary regulation
• Screening test 2,4-dinitrophenylhydrazine produces yellow precipitate turbidity
• Positive urine ketones

Answer 18

MSUD

Question 19

melanuria

• Screening test
• red color

Answer 19

sodium nitroprusside test

Question 20

• increase in homocystine throughout the body
• Defect in methionine metabolism
• (+) cyanide-nitroprusside test plus (+) silver nitroprusside test

Answer 20

homocystinuria

Question 21

• parenteral feeding
• ingestion of large amounts of fruit

Answer 21

fructosuria

Question 22

Cyanide-Nitroprusside Test

False-positives:
(?), (?)

Answer 22

• ketonuria
• homocystinuria

Question 23

melanuria

• Interference à add glacial acetic acid (reverts color greenish-black)
• Acetone
• Creatinine
• purple
• amber

Answer 23

sodium nitroprusside test

Question 24

DNPH test interference

• Large doses of (?)
• a positive reagent strip test result for (?) produce a positive DNPH result

Answer 24

• ampicillin
• ketones

Question 25

* deficiency in any of three enzymes, galactose-1-phosphate uridyl transferase (GALT), galactokinase and UDP-galactose-4-epimerase * inability to properly metabolize galactose to glucose

Answer 25

galactosuria

Question 26

Media containing beta-2-thienylalaline, an inhibitor of Bacillus subtilis, is streaked with the bacteria; blood impregnated discs placed on the agar; phenylalanine counteracts the inhibitor, and bacteria grow around the disc

Answer 26

guthrie blood test

Question 27

* Failure to inherit the gene to produce the enzyme hypoxanthine guanine phosphoribosyl-transferase * severe motor defects * mental retardation * tendency toward self destruction * Gout * renal calculi * Presence of uric acid crystals resembling orange sand in diapers * Microscopic--presence of increased uric acid crystals in pediatric urine specimens

Answer 27

lesch-nyhan disease

Question 28

* Mental retardation * Bone marrow transplants and gene replacement therapy * acid-albumin (turbidity after 30 mins) * cetyltrimethylammonium bromide (CTAB) turbidity tests (turbidity after 5 mins) * Metachromatic staining (blue spot)

Answer 28

sanfillippo syndrome

Question 29

* skeletal structure is abnormal and there is severe mental retardation * mucopolysaccharides accumulate in the cornea of the eye. * Bone marrow transplants and gene replacement therapy * acid-albumin (turbidity after 30 mins) * cetyltrimethylammonium bromide (CTAB) turbidity tests (turbidity after 5 mins) * Metachromatic staining (blue spot)

Answer 29

hurler syndrome

Question 30

accumulation of organic acids further down in pathway

Answer 30

organic acedemias

Question 31

* errors in the metabolic pathway converting isoleucine, valine, threonine, and methionine to succinyl coenzyme A * p-nitroaniline urine Test (emerald green)

Answer 31

methylmalonic acidemia

Question 32

* have noticeable odor of sulfur * Inherited disorder affecting renal reabsorption * Two modes of inheritance: 1. only cystine and lysine are not reabsorbed 2. cystine, lysine, arginine, and ornithine are not reabsorbed * Increased calculi formation early in life for both modes * More common in 4 amino acids inheritance * elevated amino acid cystine in urine (+) cystine crystals in urine * inability of the renal tubules to reabsorb cystine filtered by the glomerulus * Cyanide-nitroprusside Test (red-purple color)

Answer 32

cystinuria

Question 33

early degradation products accumulate

Answer 33

maple syrup urinde disease (MSUD)

Question 34

* Sweaty feet odor of urine * Accumulation of isovalerylglycine * isovaleryl coenzyme A deficiency in the leucine pathway * MS/MS

Answer 34

isovaleric acidemia

Question 35

seen during pregnancy and lactation

Answer 35

lactosuria

Question 36

# homogentistic acid test * Screening test for metabolic disorder * transient deep blue color in test tube

Answer 36

FeCl3 test

Question 37

# homogentistic acid test * test for reducing substance * yellow precipitate

Answer 37

clinitest

Question 38

* Metabolic defects * Underdevelopment of liver function * Acquired severe liver disease * Ferric chloride produces a transient green color—do not confuse with phenylalanine * Nitroso-naphthol produces an orange-red color

Answer 38

tyrosyluria/tyrosinemia

Question 39

* Second pathway for tyrosine * Pigment for dark hair, skin * Defect causes albinism * Increased production = malignant melanoma * Dark urine from oxidation of melanogen * Black precipitate with ferric chloride * Red color with sodium nitroprusside

Answer 39

melanuria

Question 40

* Tryptophan enters intestine; is reabsorbed or is converted to indole by bacteria and leaves in the feces * Intestinal disorders and Hartnup disease cause increased tryptophane conversion to indole * Hartnup disease: blue diaper syndrome * Inherited disorder affects intestinal reabsorption of indole and renal tubular reabsorption = Fanconi syndrome * Requires dietary supplements * Urine: blue or violet color with ferric chloride that can be extracted into chloroform * Increased indole reabsorbed, excreted by kidney on its way to the liver * Exposure of urine to air = indigo blue

Answer 40

indicanuria

Question 41

# homogentistic acid test * Screening test * add alkali to freshly voided urine * observe for darkening of the color (ascorbic acid interferes the test)

Answer 41

Urinary Homogentisic Acid Test