Urine Analysis:- Part 4 – Chemical Examination and Interpretations
Sample for urine analysis
- Preferably use freshly voided urine.
- If there is a delay, then refrigerate the urine.
- The morning sample is concentrated urine.
Precautions for urine analysis
- Preferably examine the urine within the first 30 minutes.
- Reject unlabelled urine sample.
- Avoid fecal or menstrual blood contamination.
- A normal healthy person will have daily protein exertion of 100 mg/day. This is a very small proportion of the total plasma protein.
- It is mostly the albumin because of the smaller size. There is a small fraction of globulin as well.
- The proximal tubules reabsorb most of the protein filtered in the glomerular filtrate.
- So proteinuria may be due to:
- As a result of increased filtration from the glomerulus.
- Or it is decreased reabsorption from the tubules.
- Proteinuria is the first indicator of renal disease.
- The random sample is negative.
Clinical types of proteinuria are:
- This is caused by nonrenal diseases and is transient; it is seen in:
- Acute phase proteinuria.
- This is usually not detected by the routine urine reagent strips.
- This is due to renal diseases involving glomeruli or tubules.
- Albumin appears in the urine in glomerular damage, followed by the WBCs and RBCs.
- It is seen in:
- Streptococcal glomerulonephritis.
- Strenuous exercise (reversible condition).
- Pre-eclampsia and hypertension. (reversible condition).
- Toxic heavy metals.
- Severe viral infection.
- Proteins can be added as the urine passes through the ureter, urinary bladder, and urethra.
- Bacterial and fungal infection of the lower urinary tract,
- Menstrual contamination also contains proteins.
- Prostatic fluid and spermatozoa.
Orthostatic or postural proteinuria:
- This is a persistent benign condition frequently seen in young patients.
- It appears when the person is upright and disappears when the patient lies down.
- Procedure to confirm the diagnosis:
- These patients are advised to empty their bladders before going to bed.
- Take the first urine sample when patients get up.
- Take another sample when patients are upright for several hours.
- The first sample will be negative.
- The second sample will be positive in orthostatic proteinuria.
- This is seen in diabetic nephropathy.
- This microalbuminuria indicates diabetic complications.
- The further complication of diabetes can be prevented by controlling diabetes.
- This is also associated with an increased risk of cardiovascular diseases.
- Microalbuminuria is reported as albumin excreted as µg/min or in mg/24 hours.
- The level is significant from 20 to 200 µg/min Or 30 to 300 mg/24 hours.
- The albumin/creatinine ratio is >3.4 mg/mmol in these cases.
- The first-morning specimen is recommended.
Bence Jones proteinuria (BJ):
- It is seen in multiple myeloma patients.
- These are monoclonal light-chain immunoglobulins.
- This is a low molecular weight protein and is excreted in the urine.
Procedure to detect BJ protein:
- Heat the urine, and these proteins coagulate at 40 to 60 °C.
- Dissolve when the temperature reaches 100 °C.
- Reading the result: Urine turbid at 40 to 60 °C and clear at 100 °C is considered positive.
Type and degree of proteinuria:
|Degree of proteinuria||Amount of protein excreted in the urine||Etiology
1. Chronic pyelonephritis
2. Polycystic kidneys
3. Renal tubular diseases
Normal urine protein :
- In 24 hours of urine, 150 mg or 20 mg/dL. ( another source = it is 0 to 0.1 gm).
- Another source: Protein in the urine is <10 mg/dL or 100 mg/24 hours.
- This protein consists of mainly low molecular weight serum proteins, so the major protein is the albumin seen in the urine.
- Other proteins include serum and tubular microglobulins, Tamm Horsfall protein produced by the tubules, and proteins from the prostate and vaginal secretions.
How to check proteinuria:
- Mostly urine strips are used as a screening for proteinuria. These strips are specific for albumin.
- False-positive results are seen in the following:
- In alkaline urine.
- In highly buffered urine.
Reagent test strip test for protein in the urine:
Various urine tests for proteins and their characteristics:
|Characteristics||Heat and acid||Reagent strip||Salfosalicylic acid|
Clinical types of proteinuria and etiology:
|Clinical type of proteinuria||Etiology of proteinuria|
- Because of the diagnosis of diabetes mellitus, a glucose test in the urine is very commonly advised.
- The blood glucose and urine glucose tests are part of a routine check-up.
- Early diagnosis of diabetes mellitus helps improve the prognosis and complications of diabetes mellitus.
- Glucose filtered in the glomerular filtrate is almost all absorbed by the proximal convoluted tubules; therefore, there will be a negligible amount of glucose in the urine.
- Tubular absorption of glucose is an active process that depends upon the body’s needs.
- In diabetes mellitus, tubular transport of glucose ceases, and glucose appears in the urine.
- In hyperglycemia, the tubular transport of glucose stops, and glucose starts appearing in the urine.
- For testing diabetes mellitus, take after the 2 hours of the meal.
- The first-morning sample does not give a real picture of the last evening meal. Void the first sample and then collect the next sample.
- The renal glucose threshold is 160 to 180 mg/dL.
Normal glucose in the urine:
- A random sample is negative (qualitatively is negative).
- In 24 hours, urine glucose is 0 to 0.3 grams.
- Another source, glucose in random urine, is <30 mg/dL.
- Glucose in urine during pregnancy is called gestational diabetes.
- This is usually seen around the 6 months of pregnancy.
- Hormones secreted by the placenta during pregnancy are believed to block insulin’s action and lead to hyperglycemia.
- It is seen when the blood glucose level is normal, and glucose appears in the urine.
- Renal tubules’ absorption of glucose by the tubules is compromised.
- It is usually seen in end-stage kidney diseases, osteomalacia, and Fanconi’s syndrome.
- Glucose false tests are seen in the urine’s high specific gravity and contain a large amount of ascorbic acid.
Hyperglycemia of nondiabetic origin is seen in:
- It is seen in the following conditions:
- Pancreatic cancer.
- Cushing’s syndrome.
- The above conditions produce hormones like glucagon, epinephrine, cortisol, thyroxine, and growth hormone.
- These hormone acts against insulin and leads to glycogenolysis.
Glucose in the urine can be checked by:
- Reagents strips, glucose oxidase reaction.
- Copper reduction method.
Glucose-oxidase reagent strips:
- This test is specific for the β-isomer of glucose.
- It converts glucose in the presence of oxygen to gluconic acid and hydrogen peroxide.
- The serum glucose concentration is proportional to the oxygen consumed in the reaction or the H2O2 produced.
- In the second step, peroxidase catalyzes the reaction between H2O2 and chromogen to form the oxidized colored compound, indicating the presence of glucose in the urine.
- The result is reported as follows:
- Trace, 1+, 2+, 3+, 4+
- These colors also provide quantitative measurements ranging from 100 mg/dL to 2000 mg/dL or 0.1% to 2%.
Copper reduction method (Benedict’s reaction):
- This test was used in the early days.
- An alkaline cupric sulfate solution oxidizes all reducing sugars like glucose, galactose, fructose, maltose, xylulose, arabinose, and ribose.
- It forms a brick-red to yellow precipitate of Cu2O.
- This test is based on reducing copper sulfate (CuSO4) to cuprous oxide in the presence of alkali and heat.
- The color depends upon the amount of Cu2O.
- The color changes from blue = Negative ( CuSO4).
- Green, yellow, orange/red = Positive 4+ (CuO).
- Greenish = 1+ to Yellow = 4+
- The positive reaction of 1+ = Roughly 50 mg/dL.
- The positive reaction of 4+ = 2 or more g/dL.
Principle of Benedict’s reaction:
Comparison of Benedict reaction and Oxidase method:
|Characteristics||Benedict reaction (CuSO4)||Glucose oxidase|
|Minimum level detected||Glucose 50 to 250 mg/dL||Glucose 50 mg/dL|
|Other sugars detected||
- Ketone bodies are absent in the normal person.
- These are seen in patients with uncontrolled diabetes mellitus.
- These can also be seen in person on a low carbohydrate diet.
- These are seen in people on a high-fat diet.
Indications for the ketone bodies:
- Diabetic acidosis.
- Malabsorption syndrome.
- Pancreatic disorders.
- Insulin dosage monitoring.
- Strenuous exercise.
- Inborn error of amino acid metabolism.
Ketones are the intermediate products of fat metabolism, and these are:
- β-hydroxybutyric acid.
- Normally no ketone bodies are found in the urine because all the metabolized fats are completely broken down to CO2 and H2O.
- When the carbohydrate source of energy is unavailable, body fat stores are mobilized to supply energy, and ketones are found in the urine.
- Ketone bodies formation in diabetic patients.
- In diabetic patients, ketonuria shows a deficiency of insulin.
- It needs to adjust the dose of insulin in diabetic patients.
- The increased amount of ketones in the blood leads to electrolyte imbalance and dehydration.
- If this is not corrected, it leads to acidosis, and ultimately the patient goes into a coma.
- These ketone bodies’ ratio is different, acetoacetate 20%, acetone 2%, and β-hydroxybutyrate 78%.
Normal ketone bodies:
- These are negative in the random sample.
- Qualitatively is also negative.
Urobilinogen in the urine
- It is a colorless compound, and it forms in the intestine by the bacterial enzyme from the reduction of bilirubin action.
- Normal urine contains small traces of urobilinogen.
- Because of the fewer number of intestinal bacteria, infants have decreased urobilinogen in the urine.
- It is decreased after the antibiotics therapy because of the decreased number of intestinal bacteria.
- Urobilinogen is a bile pigment like bilirubin, and hemoglobin degradation forms it.
- It is formed in the intestine from the bilirubin by the action of the intestinal bacteria.
- Most of the urobilinogen is reabsorbed into the blood circulation (enterohepatic circulation), and some of this is excreted through the kidney into the urine.
- It is oxidized to urobilin in the feces and gives a characteristic brown color to stool.
- So usually, a urine test for urobilinogen is positive. There is normally <1 mg/dL or Ehrlich unit in the urine. So it is necessary to test for bilirubin and urobilinogen to diagnose liver diseases.
- Absent urobilinogen in the urine and feces is diagnostic of biliary duct obstruction.
Urobilinogen in different conditions:
|Urine test||Hemolytic disease of the newborn||Hemolytic anemia||Acute liver cell injury||Chronic liver cell injury||Intrahepatic cholestasis||Biliary obstruction||Cirrhosis|
|Urobilinogen in urine||Mostly absent||Increased (+++)||Increased (+)||Increased(+)||Normal or increased||Decreased or absent (pale stool)||Normal or increased|
Sample of the urine:
- A fresh urine sample is needed ( because it is light-sensitive).
- An ideal sample for detecting or quantitating is 2- hour early afternoon specimen.
- Keep in mind the diurnal variation.
Indications for urobilinogen in the urine:
- Early detection of liver diseases.
- Hemolytic diseases.
- Hepatitis and Cirrhosis.
- In carcinomas.
Differential diagnosis of urobilinogen in the urine:
|Urine test||In normal person||In liver diseases||In biliary obstruction||In hemolytic anemia|
|Bilirubin||Negative||Positive or negative||Positive (+++)||Negative|
|Urobilinogen||Normal level||Increased (++)||Absent or low||Increased (+++)|
Ehrlich aldehyde reaction:
- This is the test for urobilinogen.
- Perform this test on the fresh urine sample because it is unstable and breakdown into urobilin on keeping the urine.
- This test detects urobilinogen at least at the level of 0.1 mg/dL.
- The reagent strip is impregnated with p-dimethylamino benzaldehyde, and there is an acid buffer.
- This method may give a false-positive result due to the presence of porphobilinogen.
- Another method uses the Diazonium compound, and it forms red color.
- Result: Red color in positive cases.
- The reagent strip is impregnated with p-dimethylamino benzaldehyde, and there is an acid buffer.
The normal urobilinogen in the urine
- Its level with this method is 0.1 to 1.0 mg/dL.
- The level of 2 mg/dL is the cut-off point for the result to be abnormal.
- These are 0 to 4 mg / 24 hours.
- Random urine = 0.1 to 1 Ehrlich U/dL or <1 mg/dL.
- 2 hours urine = 0.1 to 1.0 Ehrlich U/2 hours or <1 mg/2 hours.
- 24 hours urine = 0.5 to 4.0 Ehrlich U/24 hours or 0.5 to 4.0 mg/24 hours.
Increased level of urobilinogen is seen in:
- Hemolytic anemia.
- Pernicious (megaloblstic) anemia.
- Malarial attack.
- Excessive bruising.
- Pulmonary infarction.
- Acute hepatitis.
A decreased level of urobilinogen is seen in:
- Complete or partial obstruction of the biliary tract.
- Biliary duct inflammation.
- Cancer of the head of the pancreas.
- Antibiotic therapy will suppress intestinal bacterial flora.
Bilirubin in the urine
- Bilirubin in the urine is called bilirubinuria.
- This will appear in the urine before the appearance of jaundice.
- Bilirubin is a pigmented yellow compound, a degradation product of hemoglobin.
- The following diagram gives the concept of the formation of bilirubin. When there is increased production, then it may appear in the urine.
- Conjugated bilirubin appears in the urine when the normal degradation cycle is disrupted by obstruction of the bile duct-like gall stones or cancer.
- Another possibility is when the liver cells are damaged and allow the leakage of bilirubin directly into the circulation.
- Hepatitis and cirrhosis are common causes of liver cell damage and result in bilirubinuria.
- Increased hemolysis does not produce bilirubinuria.
- Bilirubin in the urine is detected only if the urine sample is fresh because bilirubin decomposes rapidly in bright light.
- If the urine is left in the lab, bilirubin is converted into biliverdin, a green compound by the light not detected by the bilirubin strips.
Normal bilirubin level in urine:
- Urine bilirubin is negative (0 to 0.2 mg/dL (0 to 0.34 µmol/L).
- Bilirubin can be detected in urine by the Foam test.
The procedure of foam test for bilirubin:
- Place a small urine volume in the test tube, cap it, and shake it vigorously.
- The foam at the top is white means bilirubin is negative.
- If the foam is orange in color means bilirubin is present.
Other methods to detect bilirubin in the urine are:
- Diazo reaction in the form of tablets or Dipsticks.
- Fouchet’s test.
- Ferric chloride test.
Comparison of Fouchet’s, Ferric chloride, and Diazo reaction for Bilirubin:
||Diazo reaction (tablet or dipstick)|
Tablet = 0.2 to 0.4 mg/dL
Dipstick = 0.0 to 0.1 mg/dL
- Increased bilirubin in the urine is seen in the following:
- Hepatitis and liver diseases.
- Obstructive biliary tract disease.
- Liver or biliary tract tumors.
Hemoglobinuria causes are:
- It may result from the hemolysis of RBCs in the urinary tract. This happens in dilute and alkaline urine.
- This can also occur in intravascular hemolysis, where hemoglobin filters out through the glomeruli. No RBCs will be seen in the urine.
Pathogenesis of hemoglobinuria:
- Under normal conditions, the complex of hemoglobin+haptoglobin complex can not filter out of the glomeruli.
- This happens when the free hemoglobin exceeds the haptoglobin e.g.
- Hemolytic anemia.
- Transfusion reactions.
- Severe burns.
- Strenuous exercise.
- Malarial infection.
- This is negative.
- Myoglobin is a heme-containing protein found in muscle tissue.
- This is seen in the case of rhabdomyolysis.
- The heme portion of the myoglobin is toxic to the renal tubules; increased concentration will lead to renal failure.
- The blood hemolytic transfusion reaction may cause damage to the kidneys and leads to renal failure.
Causes of hemoglobinuria are:
- Crush syndrome.
- Muscle wasting diseases.
- Extensive exertion.
- Heroin abuse.
|History of the patient||The typical history of the patient|
|Appearance of plasma||Red color||Normal|
|Precipitation test with (NH4)2SO4||
Ammonium sulfate (NH4)2SO4) concentration test:
- It is done to differentiate hemoglobinuria and myoglobinuria:
- Most of the body’s phosphorus is combined with the calcium in the bones.
- About 15% is present in the blood, making the main intracellular anions.
- The human body contains 620 g of phosphorus, mainly in the form of phosphate.
- The urine HPO4-2: H2PO4– ratio varies over a wide range, from 1: 100 at pH 4.5 and 90:10 at pH 8.0.
- Urine for phosphorus for 24 hours collections needs acid-washed detergent-free containers.
Indication for urinary 24 hours phosphorus:
- In hyperparathyroidism.
- In hypoparathyroidism.
- In case of renal loss.
Phosphorus has many functions in the body:
- It has a role in glucose and lipid metabolism.
- It helps in the storage and transfers the energy in the body.
- It generates bony tissue.
- It maintains the acid-base balance in the body.
Normal phosphorus in urine:
- Serum level = 2.4 to 4.1 mg/dL (0.78 to 1.34 mmol/L).
- Urine = 1 gram / 24 hours.
- This also depends on the diet.
- Inorganic phosphate = 20 to 40 meq/L.
- Creatine is synthesized in the liver, pancreas, and kidneys from the amino acids arginine, glycine, and methionine.
- It is transported from blood to muscles, the brain, and other organs, converted to phosphocreatine, and acts as an energy reservoir like ATP.
- Creatinine is the waste product of creatine and phosphocreatine.
- Most of the creatinine is produced in the muscles, so it is proportional to the muscle mass.
- Creatinine enters the blood and is excreted through the kidney.
Indications for creatinine:
- To evaluate kidney diseases.
- During 24- hours of urine collection refrigerates the urine, and no preservative is needed.
Normal creatinine in urine:
- 1.0 to 1.6 gm/24 hours.
- Or 15 to 25 mg/ kg body weight / 24 hours.
- Some of the bacteria from the urinary tract convert Nitrates into nitrite.
- Bacteria containing the enzyme reductase will convert nitrate to nitrite.
- NO3 →NO2 in the presence of a reductase enzyme.
- This test is negative in yeast and gram-positive bacteria.
- The reductase enzyme is found in gram-negative bacteria like Enterobacteriaceae.
- This is available as urine reagent strips and detects urinary tract infections.
- Most infections start in the urinary bladder, and from there, it travels to the ureters, tubules, and renal pelvis and reaches the kidneys.
- This is useful for detecting the initial urinary bladder infection called cystitis.
- Cystitis will lead to pyelonephritis as a complication of cystitis, and the result is:
- Renal tissue damage.
- Impairment of renal functions.
- Sometimes lead to septicemia.
- So the detection of bacteriuria in the early stages and the treatment in time will save from all these complications.
Indications for Nitrate test:
- Monitoring of the patients who are at high risk for urinary tract infection.
- Monitoring of antibiotic therapy.
- Screening of the urine culture specimens.
- These are negative.
- A negative result does not rule out bacteriuria.
- A gram-positive pathogen does not produce a nitrate-reducing substance like:
- Sodium is the primary regulator for retaining or excreting water and maintaining acid-base balance.
- Sodium also maintains the normal electrolytes’ intracellular and extracellular balance. This will take place along with potassium under the effect of aldosterone.
Indication for urinary sodium:
- Electrolytes imbalance.
- Acute renal failure.
- Na+ excreted for diagnosis of renal and adrenal imbalance. No preservative is needed for the collection for 24 hours ; only refrigerate during the collection.
Increased sodium in urine is seen in:
- Addison’s disease (adrenal failure, primary and secondary).
- Renal tubular acidosis.
- Diabetic acidosis.
- Tubulointerstitial disease.
- Salt-losing nephritis.
- Barrter’s syndrome
A decrease in urinary sodium is seen in the following:
- Excessive sweating and diarrhea.
- Prerenal azotemia.
- Cushing’s syndrome.
- Primary aldosteronism.
- Congestive heart failure.
- Nephrotic syndrome with acute oliguria.
Normal sodium in urine:
- Adult = 40 to 220 meq/24 hours urine (40 to 220 mmol/day)
- Child = 41 to 115 meq/24 hours urine (41 to 115 mmol/day)
- Value is salt intake dependent.
- Potassium acts as a body buffer system and serves an important role in the maintenance of electrolyte balance.
- The potassium study is helpful for the study of renal and adrenal disorders.
- Potassium in the urine is in the form of KCL, K2SO4, and K2PO4 salts.
- K+ values <20 meq/L are associated with nonrenal causes.
- K+ >20 meq/L are associated with renal causes.
Indications for K+ estimation:
- To evaluate the electrolyte imbalance.
- Renal disorders.
- Adrenal glands disorder.
- For collecting urine for 24 hours, no preservative is needed; only refrigerate the sample during collection.
Normal potassium in urine:
- Adult = 25 to 125 meq/24 hours urine (25 to 125 mmol/day).
- Child = 10 to 60 meq/24 hours urine (10 to 60 mmol/day)
- Values are diet-dependent.
Increased urinary K+ is seen in:
- Diabetic and renal tubular acidosis.
- Primary renal diseases.
- Cushing’s syndrome.
- Primary and secondary aldosteronism.
- Fanconi’s syndrome.
- The onset of metabolic alkalosis.
The decreased urinary K+ value is seen in the following:
- Addison’s disease.
- In patients with K+ deficiency.
- Pyelonephritis and glomerulonephritis.
- The parathyroid gland hormones maintain calcium hemostasis.
- An adequate amount of calcium is excreted in the stool, and a small amount is in the urine.
- Calcium absorption is dependent upon dietary calcium intake.
Indications for calcium in the urine:
- To evaluate the calcium intake.
- To evaluate the rate of absorption from the intestine.
- To find resorption from the bone.
- To evaluate the renal loss.
Normal calcium in urine:
- Normal diet = 100 to 300 mg/24 hours (2.50 to 7.50 mmol/day)
- Low calcium diet = 50 to 150 mg/24 hours (1.25 to 3.75 mmol/day)
- Another source:
- 5 to 12 meq/L
- < 150 mg/ 24 hours on a low calcium diet.
- Or o.3 g/24 hours of urine.
Increased calcium in urine is a result of the following:
- Increased intestinal absorption.
- A lake of renal tubular reabsorption.
- Resorption or loss of calcium from the bones.
- Or there is a combination of the above mechanism.
- Calcium is present in urine as CaCl2, CaSO4, and CaPO4 salts.
- Urinary calcium does not have much value in the differential diagnosis of diseases.
Increased urine calcium is seen in:
- Hyperparathyroidism in 30 to 80% of the cases.
- Paget’s disease.
- Renal tubular acidosis.
- Vitamin D intoxication.
- Fanconi’s syndrome.
- Idiopathic hypercalciuria.
- Osteitis deforms.
- Bone metastasis in osteolytic type.
- Multiple myeloma.
A decrease in urinary calcium is seen in the following:
- Vitamin D deficiency.
- Metastatic carcinoma of the prostate.
- Malabsorption syndrome:
- Celiac disease.
- Sprue disease.
- Renal osteodystrophy.
- Renal failure, acute nephrosis, and nephritis.
- Vitamin-D resistant Rickets.
- Chloride is most often associated with sodium balance and fluid changes.
- Mostly urinary excretion of chloride is parallel to the dietary intake.
- This also reduces dietary salt intake, especially in patients with cardiovascular diseases, hypertension, kidney diseases, and liver diseases.
Indications for chloride:
- It is advised in electrolyte imbalance.
- In the case of dehydration.
- In metabolic alkalosis.
- For collecting the urine, no preservative is needed; only refrigerate the samples.
Normal chloride in urine:
- Children’s values are much lower than adult values.
- The values vary with the salt intake and perspiration.
- The values vary from different lab values.
Age Value in 24 hours of urine Child <6 years 15 to 40 meq/day (15 to 40 mmol/day) Children 10 to 14 years 64 to 176 meq/day (64 to 176 mmol/day Adult 140 to 250 meq/day (140 to 250 mmol/day)
- Magnesium excretion through the urine controls the blood magnesium level.
- Urinary excretion of magnesium is dependent upon dietary intake.
- If somebody takes 200 to 500 mg/day, then urinary excretion of magnesium is 75 to 150 mg/24 hours (3 to 6 mmol/day).
Indications for magnesium:
- It is advised in magnesium metabolism.
- Electrolytes balance.
- Advised in nephrolithiasis.
- For collecting the 24-hour urine sample, 20 mL of 6N HCL is needed in a metal-free container. Also, refrigerate the sample.
Normal magnesium in urine:
- Urine = 75 to 150 mg/24 hours
- urine = 3.0 to 6.0 meq/24 hours (3.0 to 6.0 mmol/day)
- 2 to 12 meq/L
Increased urine magnesium is seen in:
- Chronic glomerulonephritis.
- Increased level of blood alcohol.
- Bartter’s syndrome.
Decreased urine magnesium is seen in:
- Magnesium deficiency.
- Chronic renal diseases.
- Hypercalciuria. It is seen in long-term parenteral therapy.
- Decreased renal function like Addison’s disease.
- Free amino acids are found in the urine and acid filtrate of the protein-containing fluids.
- This test is advised when there are suspected genetic abnormalities, patients with mental retardation, reduced growth, or unexplained symptoms.
Indications for an amino acid in urine:
- This is advised for the screening of the inborn error of metabolism.
- Advised for genetic abnormalities.
- For collecting the 24 hours of urine, no preservative is needed; only refrigerate while collecting the samples.
Normal amino acids in urine:
The details are seen in part 1, complete urine analysis.