Nephrology Review – Lab Values, CKD, Dialysis & AKI

Question-and-Answer flashcards summarize essential nephrology lab values, calculations, CKD staging, management strategies, dialysis details, and AKI criteria for exam preparation.

What is the normal serum sodium (Na⁺) range?

135–145 mEq/L

What is the normal serum potassium (K⁺) range?

3.5–5 mEq/L

What is the normal Blood Urea Nitrogen (BUN) range?

8–20 mg/dL

What is the normal serum creatinine (SCr) range?

0.7–1.3 mg/dL

Give the equation to calculate corrected calcium when albumin is low.

Corrected Ca = measured Ca + [0.8 × (4 – albumin)]

What is the normal fasting blood glucose?

65–109 mg/dL

Provide the normal total serum calcium range.

8.6–10.3 mg/dL

What is the normal chloride (Cl⁻) range?

97–110 mEq/L

Give the normal serum bicarbonate (CO₂) range.

22–26 mEq/L

What are the normal AST and ALT ranges?

AST: 11–47 IU/L, ALT: 7–53 IU/L

State the normal magnesium range.

1.3–2.2 mEq/L

What is the normal phosphate range?

2.5–4.5 mg/dL

Normal albumin range?

3.5–5 g/dL

Normal hemoglobin (Hgb) for males and females?

Male: 13–18 g/dL; Female: 12–16 g/dL

Formula for Absolute Neutrophil Count (ANC)?

ANC = WBC × (% segs + % bands)

Normal platelet count and definitions of thrombocytosis & thrombocytopenia?

150–350 k/µL; >400 k = thrombocytosis; <150 k = thrombocytopenia

What BUN:SCr ratio suggests decreased effective circulating volume (e.g., dehydration)?

20:1 (elevated) – normal is 10–15:1

Normal estimated GFR for healthy men and women?

Men: 127 ± 20 mL/min/1.73 m²; Women: 118 ± 20 mL/min/1.73 m²

List the seven components of a Basic Metabolic Panel (BMP).

Na⁺, K⁺, Cl⁻, CO₂ (bicarb), BUN, SCr, Glucose

What additional labs are included in a Complete Metabolic Panel (CMP) beyond BMP?

Albumin, Calcium, Hepatic panel (AST, ALT, ALP, bilirubin, etc.)

Normal TSH, total T4, and free T4 ranges?

TSH: 0.4–5 mIU/L; Total T4: 4.6–11.2 µg/dL; Free T4: 0.8–1.8 ng/dL

High TSH indicates ; low TSH indicates .

Hypothyroidism; Hyperthyroidism

What HbA1c is considered normal?

< 6 %

State the Cockcroft-Gault equation for CrCl (men).

CrCl = [(140 – age) × BW] / (SCr × 72)

How is Cockcroft-Gault modified for females?

Multiply the result by 0.85

Which weight is used in Cockcroft-Gault if actual body weight (ABW) < ideal body weight (IBW)?

Use actual body weight

Which weight is used if ABW is 100–130 % of IBW?

Use IBW

Provide the formula for Adjusted Body Weight (AdjBW).

AdjBW = IBW + 0.4 × (ABW − IBW)

List three main initiation risk factors for chronic kidney disease (CKD).

Diabetes mellitus, Hypertension, Glomerulonephritis

Give the GFR cutoffs for CKD stages I through V.

I ≥90, II 60–89, IIIa 45–59, IIIb 30–44, IV 15–29, V <15 mL/min/1.73 m²

Dietary protein recommendation for CKD stage IV (GFR <30).

~0.8 g/kg/day

Target HbA1c range in diabetic CKD patients.

~< 6.5 % to < 8 % depending on comorbidities

When should metformin be reduced and discontinued based on eGFR?

Reduce if eGFR <45; discontinue if eGFR <30 or on dialysis

At what eGFR should SGLT2 inhibitors not be initiated?

Do not start if eGFR <30 mL/min/1.73 m²

Blood-pressure goal for CKD (non-dialysis) patients.

< 120/80 mm Hg

First-line antihypertensive class for CKD with proteinuria.

ACE inhibitors or ARBs

How much should proteinuria be reduced when titrating ACEI/ARB?

Aim for 30–50 % reduction even if BP is controlled

Hemodialysis patients’ BP goal.

< 130/80 mm Hg

Anemia work-up thresholds for CKD: Hgb < ___ in females and < ___ in males.

< 12 g/dL (females); < 13 g/dL (males)

When is iron replacement initiated in CKD anemia?

TSAT ≤ 30 % AND ferritin ≤ 500 ng/mL

Daily elemental iron goal for oral therapy in CKD.

~200 mg/day elemental iron

Criteria to start ESA therapy in CKD.

Hgb falling and between 9–10 g/dL (start); target 10–11 g/dL

Most common adverse effect of ESA therapy.

Hypertension

Name two first-line phosphate binders for secondary hyperparathyroidism in CKD.

Calcium carbonate and calcium acetate

Which non-calcium phosphate binder also lowers LDL?

Sevelamer HCl

Which calcimimetic is used to lower PTH in CKD?

Cinacalcet HCl

First-line treatment for metabolic acidosis in stage 4–5 CKD.

Alkalinizing salts such as sodium bicarbonate

Preferred vascular access for long-term hemodialysis.

Arteriovenous (AV) fistula

How long does an AV fistula typically take to mature?

1–2 months (usually placed ~1 year before HD need)

Differentiate high-flux from conventional dialysis membranes.

High-flux membranes have larger pores and remove high-molecular-weight substances faster, shortening treatment time.

List two key benefits of Continuous Renal Replacement Therapy (CRRT).

Better hemodynamic stability and less risk of fluid overload in critically ill

Define Acute Kidney Injury (AKI) according to RIFLE ‘Risk’ stage for SCr.

SCr increase 1.5–2 × baseline

What urinary finding is characteristic of acute tubular necrosis (ATN)?

Dirty brown / muddy granular casts

Name two drug classes commonly causing prerenal AKI.

Diuretics (volume depletion) and ACE inhibitors (efferent dilation)

Most common drug cause of toxic ATN.

Aminoglycoside antibiotics

Most common cause of acute interstitial nephritis (AIN).

Drug hypersensitivity (e.g., penicillins, sulfonamides, ciprofloxacin, phenytoin)

Give three nephrotoxic drugs that commonly induce AKI.

NSAIDs, Amphotericin B, Radiocontrast media (plus ACE/ARB, aminoglycosides, etc.)

Best strategy to prevent contrast-induced nephropathy.

Adequate IV hydration with normal saline

Name two antioxidants sometimes used to prevent contrast-induced nephropathy.

Ascorbic acid and N-acetylcysteine

Define anuria per AKI criteria.

Urine output < 50 mL/day

What does a BUN:SCr ratio > 20:1 generally suggest?

Prerenal azotemia or hypovolemia

Which laboratory panel includes WBC, Hgb, Hct, and platelets?

Complete Blood Count (CBC)

What is the mnemonic ‘fish-bone’ primarily used to depict?

Quick schematic of Na | Cl | BUN / Glucose and K | CO₂ | SCr values in labs

Which vitamin D analogs can be used in later-stage CKD without further renal activation?

Calcitriol, paricalcitol, doxercalciferol

Give the recommended daily sodium limit for CKD patients per DASH diet.

< 2 g/day

Which dialysis access has the highest infection and thrombosis rates but can be used immediately?

Central venous catheter

List two anticoagulation options used during CRRT.

Unfractionated heparin or citrate solutions

Key advantage of an AV graft over a catheter for HD access.

Lower infection risk than catheters and usable within 2–3 weeks

What is the primary non-pharmacologic treatment for pruritus in CKD?

Antihistamines (others: 5-HT3 blockers, gabapentin)

At what SCr or eGFR should planning for renal replacement therapy start?

Start planning when CrCl/eGFR < 25 mL/min or SCr > 4 mg/dL (CKD stage IV)

Which oral phosphate binder also delivers iron and may raise TSAT?

Ferric citrate (Auryxia)