L’analyse d’urine et les glomerulon é phrites Dr Tim Meagher ExamOne Canada AQTV, Qu é bec, 2008

L’analyse d’urine Apparence Apparence gravité spécifique gravité spécifique Cellules: leucocytes, globules rouges Cellules: leucocytes, globules rouges hémoglobine hémoglobine Protéines Protéines bactéries bactéries Cylindres, rouges, blancs, hyaline Cylindres, rouges, blancs, hyaline

Gravit é sp é cifique Gravit é sp é cifique Une mesure de concentration Une mesure de concentration Plus l’urine est concentr é plus la GS est elev é Plus l’urine est concentr é plus la GS est elev é Plus l’urine est dilu é plus la GS est bas Plus l’urine est dilu é plus la GS est bas La GS d é pend des tubules La GS d é pend des tubules

Hématurie Globules rouges ou hémoglobine Globules rouges ou hémoglobine Gloubules rouges proviennent du rein uret è re, v é ssie ou prostate Gloubules rouges proviennent du rein uret è re, v é ssie ou prostate > 5 m é ritent une investigation > 5 m é ritent une investigation

Leucocytes Pyurie Pyurie proviennent du rein, uret è re, v é ssie, prostate, ou ur è thre proviennent du rein, uret è re, v é ssie, prostate, ou ur è thre Cystite Cystite Peuvent etre assures sans investigation Peuvent etre assures sans investigation

Bact é ries D é notent inflammation D é notent inflammation Infection (cystite, pyelon é phrite) Infection (cystite, pyelon é phrite) N é phrite interstitielle N é phrite interstitielle –Medicaments, r é action allergique Asymptomatique ou symptomatique Asymptomatique ou symptomatique Accompagn é es de globules blancs Accompagn é es de globules blancs

Cylindres (casts) Sont des ‘empreintes’ des tubules Sont des ‘empreintes’ des tubules Proviennent des reins Proviennent des reins D’importance vari é e D’importance vari é e B é nins: hyalines, granulaires en petite quantit é B é nins: hyalines, granulaires en petite quantit é Pathologies importantes: granulaires en grande quantit é, RBC casts Pathologies importantes: granulaires en grande quantit é, RBC casts

Protein comes in many sizes Size is described in ‘molecular weight’ Size is described in ‘molecular weight’ Low molecular weight (small) Low molecular weight (small) –Light chains Medium molecular weight (medium) Medium molecular weight (medium) –Need an example High molecular weight (large) High molecular weight (large) –albumin

How does kidney handle protein? Filters Filters Reabsorbs Reabsorbs Minimally excretes Minimally excretes

Urinary protein Some protein is normal! Some protein is normal! –150 mgs in 24 hours »10-15 mgs is albumin »Small sized plasma proteins »Pieces of renal cells ‘Proteinuria’ is an abnormal amount of protein in urine, ‘Proteinuria’ is an abnormal amount of protein in urine, –ie > 150 mgs in 24hrs.

Detecting protein in urine Dipstick (used in physician offices) Dipstick (used in physician offices) –Trace, 1+, 2+, 3+ »False positive situations exist High specific gravity (very concentrated urine) High specific gravity (very concentrated urine) Very alkaline urine Very alkaline urine »False negative situations exist Very low specific gravity (very dilute urine) Very low specific gravity (very dilute urine) Rule of thumb Rule of thumb –Protein level (mgs %) should not exceed SG (last 2 digits) »Eg if SG is 1.022, protein should be < 22 mgs% »If SG 1.30 protein should be < 30 mgs%

(IV) MEASURING PROTEINURIA Semiqualitative (Dipstix) Trace Quantitative mg/dL mg/dL mg/dL mg/dL 301 mg/dL & up

Detecting protein in urine (2) Quantitative Quantitative –Spot measurement- usually recorded in mgs% or mmol/L –24 hour urine collection »Measure protein and creatinine Cumbersome, inconsistent and unreliable Cumbersome, inconsistent and unreliable < 1G creatinine excreted: likely an incomplete collection < 1G creatinine excreted: likely an incomplete collection

PROTEINURIA (INSURANCE POPULATION) viz. 60% of cases of increased protein in urine in insurance population = due to increased albumin

Detecting protein in urine (3) protein/ creatinine ratio protein/ creatinine ratio –Independent of specific gravity or urinary volumes –> 0.2mgs/ G creatinine is abnormal » suggests tubular disease »> 1.5 suggests glomerular disease

Detecting protein in urine (4) Albumin/creatinine ratio Albumin/creatinine ratio –Proteinuria may be due to non-renal sources »Prostate, vaginal. RBC’s WBC’s –albuminuria is specific for renal disease »< 30mgs / 24 hours is N (< 3 mgs%) »‘Microalbuminuria’ is mg/24h. (3-30mgs%) »‘Macroalbuminuria’ is > 300 mg/24h. (> 30mgs%) –Albumin/ creatinine ratio > 0.3 is abnormal

Measuring urinary albumin Albumin (mgs/dl) Alb/creat (mgs/G) Alb/creatmgs/mmol 24h. urine albumin (mgs) Normal < 3 < 30 < 2.5 < 30 Microalb Macroalb > 30 > 300 > 25 > 300

Why measure albumin in urine? Better index of glomerular disease Better index of glomerular disease As glomerular disease progresses albuminuria appears first. This is called ‘microalbuminuria’ As glomerular disease progresses albuminuria appears first. This is called ‘microalbuminuria’ As amount of albumin increases we use the term ‘macroalbuminuria’ or ‘proteinuria’ (as dipstick for protein is now positive) As amount of albumin increases we use the term ‘macroalbuminuria’ or ‘proteinuria’ (as dipstick for protein is now positive)

Benign proteinurias Intermittent proteinuria Intermittent proteinuria Postural or ‘orthostatic’ Postural or ‘orthostatic’ –N supine; elevated when upright Exercise-induced Exercise-induced Febrile illnesses Febrile illnesses Contaminants: seminal, prostatic, vaginal fluids Contaminants: seminal, prostatic, vaginal fluids

Pathologic proteinurias Constant proteinurias Constant proteinurias –> 1/3 specimens (insurance) –> 3 months duration (clinical) Albuminuria Albuminuria –Microalbuminuria –Macroalbuminuria Bence-Jones proteinuria Bence-Jones proteinuria

Don’t jump to conclusions! Albumin levels vary Albumin levels vary – posture, exercise, fever, other Creatinine levels vary Creatinine levels vary –Handling delays reduce urine creatinine –creatinine production decreases with »Increasing age »Older women in particular 50% of abnormal results will be normal with re- testing! 50% of abnormal results will be normal with re- testing!

Significant proteinuias Glomerular Glomerular –Glomerulus is ‘leaky’ –Too many proteins are making way into tubule Tubular Tubular –Tubules are not reabsorbing overflow overflow –Capacity of tubules to reabsorb is overwhelmed –Tubules are working normally

structure of glomerulus arteriole collecting duct to bladder

normal glomerulus