What parameters and their value to remember for biochemistry viva

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I now have extensive data from the Goldman-Cecil Medicine reference table (TABLE 3, Appendix 2). Combined with the biochemistry-specific data from Basic Medical Biochemistry and my training knowledge, I can compile a thorough viva-ready reference. Here is the complete answer:

Biochemistry Viva: Key Parameters & Normal Values

Source: Goldman-Cecil Medicine, Appendix 2 - Clinical Chemistry Reference Intervals

1. Carbohydrate Metabolism

Parameter	Normal Value
Fasting blood glucose	70-99 mg/dL (3.9-5.5 mmol/L)
2-hr post-prandial glucose	<140 mg/dL
Impaired fasting glucose	100-125 mg/dL
Diabetes diagnosis	≥126 mg/dL (fasting)
HbA1c (normal)	<5.7%
HbA1c (prediabetes)	5.7-6.4%
HbA1c (diabetes)	≥6.5%
Pyruvate (fasting)	0.3-0.9 mg/dL (34-102 µmol/L)
Lactate (venous, rest)	4.5-19.8 mg/dL (0.5-2.2 mmol/L)
Insulin (fasting)	2-25 µIU/mL

2. Lipid Profile

Parameter	Normal / Desirable Value
Total cholesterol	<200 mg/dL (<5.17 mmol/L)
LDL cholesterol	<100 mg/dL (optimal)
HDL cholesterol (male)	≥40 mg/dL
HDL cholesterol (female)	≥50 mg/dL
Triglycerides (fasting)	<150 mg/dL (<1.7 mmol/L)
VLDL cholesterol	6-38 mg/dL

3. Plasma Proteins

Parameter	Normal Value
Total protein (serum)	6.4-8.3 g/dL
Albumin (serum)	3.5-5.0 g/dL
Globulin	2.3-3.4 g/dL
A/G ratio	1.0-2.5
Prealbumin (transthyretin)	18-45 mg/dL
C-reactive protein (CRP)	<1.0 mg/dL (<10 mg/L)
High-sensitivity CRP	<1 mg/L (low cardiovascular risk)
Fibrinogen (plasma)	200-400 mg/dL
Ceruloplasmin	16-31 mg/dL
Transferrin	200-360 mg/dL
Ferritin (male)	20-250 ng/mL
Ferritin (female)	10-120 ng/mL

4. Liver Function / Enzymes

Parameter	Normal Value
ALT / SGPT	9-60 U/L (male), 9-36 U/L (female)
AST / SGOT	10-40 U/L
Alkaline phosphatase (ALP)	25-100 U/L (adults)
GGT (male)	2-65 U/L
GGT (female)	1-35 U/L
LDH (total)	100-220 U/L
Bilirubin (total)	0.2-1.0 mg/dL
Bilirubin (direct / conjugated)	0.0-0.2 mg/dL
Bilirubin (indirect)	0.2-0.8 mg/dL
5'-Nucleotidase	2-15 U/L

5. Kidney Function

Parameter	Normal Value
Blood urea nitrogen (BUN)	7-18 mg/dL (2.5-6.4 mmol/L)
Serum creatinine (male)	0.7-1.3 mg/dL
Serum creatinine (female)	0.5-1.1 mg/dL
BUN/Creatinine ratio	10:1 to 20:1
Uric acid (male)	3.5-7.2 mg/dL
Uric acid (female)	2.5-5.7 mg/dL
GFR (normal)	≥90 mL/min/1.73 m²
Cystatin C	0.52-0.98 mg/L

6. Electrolytes & Blood Gas

Parameter	Normal Value
Sodium (Na+)	135-145 mEq/L
Potassium (K+)	3.5-5.0 mEq/L
Chloride (Cl-)	98-106 mEq/L
Bicarbonate (HCO3-)	22-29 mEq/L
Calcium (total)	8.5-10.2 mg/dL (2.1-2.6 mmol/L)
Calcium (ionized)	4.5-5.3 mg/dL (1.1-1.3 mmol/L)
Phosphorus (inorganic)	2.5-4.5 mg/dL
Magnesium	1.7-2.3 mg/dL (0.7-0.95 mmol/L)
Anion gap	8-16 mEq/L
pH (arterial)	7.35-7.45
pCO2	35-45 mmHg
pO2	80-100 mmHg
O2 saturation	95-99%

7. Cardiac Enzymes & Markers

Parameter	Normal Value
Troponin I (cardiac)	<0.04 ng/mL
Troponin T (cardiac)	<0.01 ng/mL
CK (Creatine kinase), total (male)	55-170 U/L
CK (female)	30-135 U/L
CK-MB	<5% of total CK, or <25 U/L
Myoglobin	10-92 ng/mL (male)
BNP (B-type natriuretic peptide)	<100 pg/mL
NT-proBNP	<125 pg/mL (<75 yrs)

8. Thyroid Function

Parameter	Normal Value
TSH	0.4-4.0 mIU/L
Free T4 (FT4)	0.8-1.8 ng/dL
Free T3 (FT3)	2.3-4.2 pg/mL
Total T4	5.4-11.5 µg/dL
Total T3	80-200 ng/dL

9. Hormones (Key Ones)

Parameter	Normal Value
Cortisol (8 AM)	5-25 µg/dL
Cortisol (4 PM)	3-16 µg/dL
ACTH (morning)	7-63 pg/mL
Testosterone (male)	300-1000 ng/dL
Testosterone (female)	15-70 ng/dL
Estradiol (female, follicular)	20-350 pg/mL
PTH (intact)	15-65 pg/mL
Insulin (fasting)	2-25 µIU/mL
C-peptide (fasting)	0.5-2.0 ng/mL
Prolactin (male)	2-18 ng/mL
Prolactin (female)	2-29 ng/mL

10. Vitamins & Minerals

Parameter	Normal Value
Vitamin B12	200-900 pg/mL
Folate (serum)	2-20 ng/mL
Folate (RBC)	140-628 ng/mL
Vitamin D (25-OH)	20-50 ng/mL (sufficient)
Vitamin D deficiency	<20 ng/mL
Iron (serum, male)	65-175 µg/dL
Iron (serum, female)	50-170 µg/dL
TIBC	250-370 µg/dL
Transferrin saturation	20-50%
Zinc (serum)	70-120 µg/dL
Copper (serum)	70-150 µg/dL

11. Urine Parameters (24-Hour)

Parameter	Normal Value
Total volume	600-2500 mL/day
Urine pH	4.6-8.0
Specific gravity	1.002-1.030
Protein (total)	<150 mg/day
Creatinine (male)	14-26 mg/kg/day
Creatinine (female)	11-20 mg/kg/day
Glucose (urine)	Negative / <0.5 g/day
Ketones	Negative
Calcium	100-300 mg/day
Uric acid	250-750 mg/day
Sodium	40-220 mEq/day
Potassium	25-100 mEq/day

12. Special Biochemistry Markers

Parameter	Normal Value
Amylase (serum)	27-131 U/L
Lipase (serum)	7-60 U/L
Ammonia (plasma)	18-72 µg/dL (11-35 µmol/L)
Homocysteine	4-15 µmol/L
Acetoacetate	0.5-3.0 mg/dL
Beta-hydroxybutyrate	<0.5 mmol/L (normal)
Osmolality (serum)	275-295 mOsm/kg
Osmolality (urine)	300-900 mOsm/kg
Copper (ceruloplasmin)	16-31 mg/dL
Alpha-fetoprotein (AFP)	<10 ng/mL
PSA (total)	<4.0 ng/mL

High-Yield Viva Tips

Anion gap formula: Na - (Cl + HCO3) = 8-16 mEq/L; elevated in MUDPILES (Methanol, Uremia, DKA, Propylene glycol, Isoniazid/Iron, Lactic acidosis, Ethylene glycol, Salicylates)
BUN:Creatinine >20 = pre-renal azotemia; <10 = intrinsic renal disease or low protein intake
Henderson-Hasselbalch: pH = 6.1 + log([HCO3] / 0.03 × pCO2)
Osmolal gap = Measured - Calculated osmolality; >10 mOsm/kg suggests toxic alcohol ingestion
A/G ratio <1 suggests paraproteinemias (multiple myeloma) or liver disease
Troponin peaks at 18-24 hrs post-MI, stays elevated 7-10 days (I) / 10-14 days (T)
CK-MB peaks at 24 hrs, normalizes in 48-72 hrs (used to detect re-infarction)

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