Clinical Chemistry

Tests fof Glucurine

Glucserum> 180mg/dL=> +Glucurine

– dipstick–> gluc oxidase & peroxidase–> sensitive  

gluc–> gluconate + hydrogen peroxide

– Copper sulfate method

– Copper sulfate method –> low senstivity

Which Urine proteins are detected with the dipstick method?
Only Albumin
Detection of Bence-Jones proteins

1.Unique solubility property of light chain proteins

Precipitate-400C & Re-dissolve – 100oC

when cooled–> Precipitate-600C & Re-dissolve-40oC

2.Urine protein electrophoresis

Dipstick test sensitivity for Ketones
Sensitive only–> acetoacetic acid
DDx for Dipstick + Hgb

– Myoglobinuria–> Hx: severe muscle tenderness, elevated [CK/aldolase]serum, [haptoglobin]nml

– Hemoglobinuria <– hematuria / Hemolysisintravascular

!!!Mgb = soluble in NH4SO4

 

Bilirubinurine +

Urobilinogenurine +++

DDx

 

Conjugated Hyperbilirubinemia

Hepatitis

Nitriteurine + –> Dx?

UTI –> most organisms = nitrite + (E.coli)

!!! – = enterococci, N. gonorrhea, M tb

Leukocyte esterase  + –> DDx?

UTI–> screen –>reflection of urinary neutrophils #

!!!false + <– trichomonads & eosinophils

Fixed Urinespecgrav = 1.010= Glomerular filtratespecgrav

Term & cause

Isosthenuria

tubular damage– renal medullary dysfunction

Sickle Cell disease

Renal tubular acidosis and pHurine
Kidney cannot acidify the urine beyond pH 6.5 => Inappropriately alkaline relative to pHblood
Ascorbic Acid and dipstick tests

Ascorbate –> inhibits

Dipstick tests: Gluc, Hgb, Bilirubin, nitrite, leukocyte esterase

Calcium oxalate stones

Causes of Oxaluria

Crohn’s, s/p small bowel resection/bypass, ingestion of excessive amounts of oxalate(rhubarbs, spinach, nuts)

10 hyperoxaluria –> stones in childhood

pHurine and kidney stones

–> little effect on Calcium oxalate crystallization

–> elevated pH–> Calcium Phosphate stones, struvite

–> acidotic pH–> urate stones

X linked nephrolithiasis (Dent disease)

Mutation in the voltage gated chloride channel5 gene=>

hypercalciuria–> stone

UTI w Proteus mirabilis a/w whict type of stones?

Struvite

–> urea-splitting organisms=> alkalotic pH

Common stones in Pts s/p colectomy

Rx

Urate stones-Hyperuricosuria-Rx: 1.allopurinol=xanthine oxidase inhibitor–> reduces endogenous urate

2.Urine alkalization

Cystine stone formation – Cause?
cystinuria–> autosomal recessive–>defect in renal/intestinal dibasic AACOLA transport–> Cystein = least soluble –>Rx: Urinealkaline ,Proteinrestriction

2,8-Dihydroxyadenine stones-Cause?

Rx?

deficiency – Adenine phosphoribosyl transferase

–>purine metabolism

Rx: Allopurinol

Urine Crystals

Envelopes

~ dumpells

Calcium oxalate Dihydrate(envelopes)/monohydrate (dumpells,spindle/oval)

“recieved the –envelope late-> dump it”

Pleomorphic crystals most often–> diamond/square/rod

polarize in a variety of colors

yellow-brown rhombic/hexagonal plates, needles/rosettes

Uric acid

DDx:Sulfonamide crystals–>soluble in acetone

URing w shapes/diamonds/colors”

 

Urine crystals?

“Coffin lids”

Struvite-Triple Phosphate (Mg, ammonium phosphate)

–> alkaline pH, staghorn calculi

“Coffin of Proteus–>staghorn–>struvite “

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Cysteine –> cystinuria

“Cola –> hexagonal glass bottle”

 

Urine crystals?

yellow brown needles

Bilirubin

Bins and needles”

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Sulfadiazine

<– trimethoprim-sulfadiazine administration

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Cholesterol

“cholesterol results–>broke the glass”

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Tyrosine

<–severe liver disease

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Ammonium biurate

“thorn=ankathi”

 

Urine crystals?

“Maltese cross” under polarized light

Leucine

“Leukos cross”

Leucine and Tyrosine urine crystals

Causes?

often–> severe liver disease

rare: Tyrosinosis, “Maple syrup disease”

[image]

Hyaline casts = nonspecific

<–Dehydration, vigorous exercise, renal disease

[image]

white cell cast and budding yeast

<–Tubulointerstitial nephritis

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Granular cast (acellular)~>nonspecific

<–renal disease

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Fatty cast<– Nephrotic syndrome

lipid droplets–>polarized light–> maltese cross

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Red  cell cast

<– glomerulonephritis

[image]

waxy cast

<– renal diseaserenal disease

Acute renal failure

Urine Micro: Erythrophagocytosis

Dx?

RPGN

Phagocytosis”

Acute renal failure

Urine Micro: numerous granulocytes( neutros & eos)

Dx?

AIN

“Nephritis-numerous neutros”

CSF

pink / yellow-tinged fluid following centrifucation

Term and etiology

Xanthochromia

Pink<– free Hgb–> subarachnoid hemorrhage

Yellow<–Bilirubin (12hrs,peak72hrs, t1/2=2wks)

Artifactual: hyperbili,CSFprotein>150mg/dL, carotinoids, melanin,rifambin, >1hr processing delay

Post traumatic rhinorrhea/otorrhea

tests to r/o CSF leak

[Gluc ] = [Gluc]CSF–>nonspecific

Protein electrophoresis–> twin transferrin peak ,pre-albumin band

[asialated transferrin]

elevated IgGCSF:IgGserum

Control: AlbuminCSF:Albuminserum

Dx?

 

MS

IgG index =IgGCSF:IgGserum/ control

–> exclude the effect of increase permeability

CSF-Agarose gel electrophoresis/Isoelectric focusing:

Oligoclonal bands (g-region)

 

MS

2 or >2 band = +

IEF (+IgG Ab) –>4 or > 4

Increased [IgA]CSF

Dx?

Cerebral Adrenoleukodystrophy

[Gluc]CSF < 30% (normal 60%, 60mg/dL)

Dx?

Bacterial meningitis

elevated [Glutamine]CSF

Dx?

 

Hepatic encephalopathy

Neurosyphilis

– Screening test?

– Confirmatory test?

CSF- FTA-ABS

CSF-VDRL

–> counter to serum

CSF: Protein>100, Gluc <40

Leuko’s count 1000 -10,000 diff predom Polys

Dx?

Bacterial meningitis

~ predom lymphos –> if partially treated

CSF: Protein= 20-100, Gluc< 40

Leukos count=50-500, diff: polys

Dx?

early viral meningitis–> HSV (Gluc=decreased)

lymphs–> late viral meningitis vs. fungal/mycobacterial( also Gluc–>decreased) 

 

Pleural effusions

Transudate

Causes

Most common –>CHF (larger on the right)

Cirrhosis, nephrotic syndrome–> decreased Osmotic pressure

Pleural fluid chemistries:

pH<7.2, LDH>700, Gluc<30

Dx?

most common = RA

collagen vascular diseases

Pleural effusion

elevated Amylase

Causes?

Malignancy

Esophageal perforation–> pH<6.0

Pancreatitis–> left-sided

Pleural fluid micro:

Lymphocytic effusion

sparse mesothelial cells

Dx?

s/o tuberculous effusion

Pleural fluid micro:

Eosinophils

a/w?

Following prior tap

Pleural fluid micro:

conspicuously decreased mesothelial cells

DDX?

RA/Tb/post-pleurodesis pleuritis

Pleural effusion – milky

Micro: lymphos

Triglycerides > 110mg/dL

Chylomicrons: electrophoresis +

Chylous-chylothorax

<–thoracic duct obstruction

Pleural effusion – milky

Micro: mixed leukos, cholesterol crystals

Triglycerides < 50mg/dL

Chylomicrons: electrophoresis –

Pseudochylous effusion

<– gradual accumulation of lipids<–cellular break down <–Tb, RA, myxedema

Peritoneal fluid

AlbuminSerum – Albuminascites > 1.1g/dL

Dx?

Portal hypertension

<1.1 <– other causes

+ Diagnostic Peritoneal Lavage –> Indication for exploratory labarotomy

Criteria

gross blood >15mL / RBCs > 100,000/mL

WBCs>500/mL, Gram stain: bacteria

Chest tube/ Foley catheter : peritoneal fluid 

Synovial fluid

1. elevated lactate (>250mg/dL) –> dx?

2. low complement –> ddx?

1. septic artritis

2. RA / Lupus

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Monosodium urate crystal
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Corticosteroid crystal
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Calcium pyrophosphate

<–pseudogout

Alizarin red S stain + crystals

non-birefringent

Hydroxyapatite