Urinalysis Overview

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ParameterExpected NormalResult and differential diagnosisFalse Positive/
False increase
False Negative/
False Decrease
ColourYellow
Straw-yellow
pH
Range (4.5-8.0)
5.5 – 6.5Alkali:
  • Diet (Vegetarian, low carbohydrate diet, lots of citrus fruit)
  • Systemic alkalosis (metabolic or respiratory)
  • RTA I, Fanconi, UTI (most)
  • Salicylate OD, antibiotics, acetazolomide

Acid:
  • Diet (high protein, cranberries)
  • Systemic acidosis
  • DM, DKA, starvation, COPD, diarrhoea, malabsorption
  • Phenylketonuria, renal TB, alkaptonuria
Stale sample left standing (ammoniacal)
Specific Gravity
(g/mL)
1.002 – 1.030<1.005 – DI, ATN, PN, Acute GN

1.010 – CRF, chronic GN

>1.030 – Ddehydration, SIADH, adrenal insufficiencyAlkaline urine

Alkaline urine
  • Proteinuria
  • Glucosuria
  • IV contrast
  • Colloid
ProteinNegative to trace
  • Renal: Increased renal tubular secretion, increased glomerular filtration (glomerular disease), nephrotic syndrome, pyelonephritis, glomerulonephritis, malignant hypertension
  • CVS: Benign HT, CCF, SBE
  • Other: Pre-eclampsia, gout, orthostatic proteinuria, increased plasma protein (myeloma), electric current injury, K+ depletion, Cushing’s syndrome
  • Drugs: Aminoglycosides, gold, amphotericin, NSAID, sulphonamides, penicillins
  • Concentrated urine (UO<2.5L/day)
  • Alkaline urine (pH >7.5)
  • Trace residue of bleach
  • Aceazolomide, cephalosporins, NaHCO3
  • Dilute urine (UO >5.0 litres/day)
  • Acidic urine (pH <5)
  • Bence Jones globulin associated with multiple myeloma, lymphoma and macroglobulinaemia is NOT detected by dipstick urinalysis
LeucocytesNegativePyuria
  • Contaminated specime
  • Ttrichomonas vaginalis,
  • Drugs or foods that colour the urine red
  • Intercurrent antibiotic therapy (e.g. gentamicin, tetracycline and cephalosporins)
  • Gglycosuria
  • Proteinuria,
  • High specific gravity.
  • Low bacteria count UTI (especially in women)
NitriteNegativeBacterial urinary infection (usually associated with Gram-negative bacteria)Drugs or foods that colour the urine red.
  • Ascorbic acid
  • Certain bacteria such as S. saprophyticus, acinetobacter and most enterococci
BloodNegative
  • Haematuria: trauma, infection, inflammation, infarction, calculi, neoplasia, clotting disorders or chronic infection.
  • Haemaglobinuria (intravascular haemolysis)
  • Myoglobinuria (crush injury, electrocution, rhabdomyolysis)
Hypochlorite bleach
KetonesNegative
  • Ketonuria is associated with low carbohydrate (high fat/protein) diets, starvation, diabetes, alcoholism, eclampsia and hyperthyroidism.
  • Overdose of insulin, isoniazid and isopropyl alcohol
Heavily pigmented urine.
Captopril, L-dopa, salicylates, phenothiazines
Underestimate the presence of ketonaemia (beta-hydroxybutyric acid can not be assessed on dipstick)
BilirubinNegative
  • Raised conjugated bilirubinaemia (with bilirubinuria) is associated with hepatocellular disease, cirrhosis, viral and drug induced hepatitis, biliary tract obstruction (e.g. choledocholithiasis), pancreatic causes of obstructive jaundice (e.g. carcinoma of the head of the pancreas) and recurrent idiopathic jaundice of pregnancy
  • Inherited condition: Dubin-Johnsons syndrome, Rotor’s syndrome
Phenothiazines
  • Ascorbic acid (vitamin C)
  • Aged sample (conjugated bilirubin hydrolses to unconjugated bilirubin at room temperature)
  • Rifampicin
  • Exposure to UV light (converts bilrubin to biliverdin)
Urobilinogen0.2-1.0 mg/dL

<17micromol/L
  • Increased: cirrhosis, infective hepatitis, extravascular haemolysis, haemolytic anaemia, pernicious anaemia, malaria, and hepatitis secondary to infectious mononucleosis
  • Decreased: or absent in obstructive jaundice and elevated levels of bilirubinuria
GlucoseNegative
  • Hyperglycaemia associated with diabetes, cystinosis, Cushings syndrome or thyrotoxicosis. Liver disease (e.g. Wilsons disease)
  • Renal: Reduced ‘renal threshold’, renal tubular disease and pregnancy
  • Drugs: cephalosporins, penicillins, nitrofurantoin, methyldopa, tetracycline, lithium, carbemazepine, phenothiazines, steroids and thiazides
Hydrogen peroxide or bleachAscorbic acid (vitamin C) or fruit juice. Some dipsticks are affected by increased specific gravity and ketonuria

References and Links


CCC 700 6

Critical Care

Compendium

Emergency physician MA (Oxon) MBChB (Edin) FACEM FFSEM with a passion for rugby; medical history; medical education; and informatics. Asynchronous learning #FOAMed evangelist. Co-founder and CTO of Life in the Fast lane | Eponyms | Books | vocortex |

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