Disorder	Clinical clues	Urine sediment	Protein-creatinine ratio	Additional tests
Diabetes mellitus	Diabetes for > 15 years, retinopathy	RBCs in < 25 percent of affected patients	> 30 to > 3,500 mg of protein per g of creatinine	Fasting blood sugar, A1C
Essential hypertension	Left ventricular hypertrophy, retinopathy	Benign	> 30 to 3,000 mg of protein per gram of creatinine	No additional tests
Glomerulonephritis	History and physical examination: infections; rash, arthritis; patient older than 40 years	Dysmorphic RBCs or RBC casts	> 30 to > 3,500 mg of protein per g of creatinine	C3 and C4 for all patients
				Tests for infections: anti-ASO, ASK, HIV, HBsAg, HCV, RPR, blood cultures
				Tests if there is rash or arthritis: ANA, ANCA, cryoglobulin, anti-GBM
				Tests if patient is older than 40 years: SPEP, UPEP
Interstitial nephritis	Medications, fever, rash, eosinophilia	WBCs, WBC casts, eosinophils	30 to 3,000 mg of protein per g of creatinine	ACE level; SS–A, SS–B
Low flow states	Volume depletion, hypotension, congestive heart failure, cirrhosis, atherosclerosis	Hyaline casts, eosinophils	< 200 mg of protein per g of creatinine	FENa: < 1 percent; eosinophilia
Urinary tract obstruction	Urinary symptoms	Benign, or RBCs	None	KUB radiography, intravenous pyelography, spiral CT scanning, renal ultrasonography
Chronic urinary tract infection	Urinary symptoms	WBCs, RBCs	< 2,000 mg of protein per g of creatinine	Pelvic examination, urine culture, voiding cystourethrography, renal ultrasonography, CT scanning
Neoplasm, paraproteinemia	Patient older than 40 years, constitutional symptoms, anemia	RBCs, RBC casts, granular casts	False-negative result or > 30 to > 3,500 mg of protein per g of creatinine	SPEP, UPEP, calcium level, ESR
Cystic kidney disease	Palpable kidneys with or without family history of cystic kidney disease, flank pain	RBCs	30 to 3,000 mg of protein per g of creatinine	Renal ultrasonography or CT scanning if there is a complex kidney cyst or mass
Renovascular disease	Late-onset or refractory hypertension, sudden onset of hypertension in young woman, smoking history, abdominal bruit	Benign	< 200 mg of protein per g of creatinine	Renal Doppler ultrasonography, radioisotope renal scanning, MRA, renal angiography
Vasculitis	Constitutionalsymptoms, peripheral neuropathy, rash, respiratory symptoms	RBCs; granular casts	> 30 to > 3,500 mg of protein per g of creatinine	C3, C4, ANA, ANCA; HBsAg, HCV, cryoglobulins, ESR, RF, SS–A, SS–B, HIV