Unit Converter
Red Blood Cell Distribution Width (RDW-CV)
(Measure of Circulating Proteins - Reflects Nutritional Status, Liver Function & Plasma Volume)
Synonyms
- Total protein
- Serum total protein
- Plasma total protein
- TP
- Total serum proteins
Units of Measurement
- g/L
- g/dL
- g/100 mL
- g%
- mg/mL
Unit Conversions
Core Relationships
1 g/dL=10 g/L1\ \text{g/dL} = 10\ \text{g/L}1 g/dL=10 g/L 1\ \text{g/100 mL} = 1\ \text{g/dL} = \text{g%} 1 mg/mL=1 g/L1\ \text{mg/mL} = 1\ \text{g/L}1 mg/mL=1 g/L 1 g/L=0.1 g/dL1\ \text{g/L} = 0.1\ \text{g/dL}1 g/L=0.1 g/dL
Quick Conversion Table
| Unit | Equivalent |
| 70 g/L | 7.0 g/dL |
| 6.5 g/dL | 65 g/L |
| 1 mg/mL | 1 g/L |
| 7 g% | 7 g/dL |
Description
Total protein represents the sum of all proteins present in serum or plasma, primarily:
- Albumin (~60%)
- Globulins (~40%)
- Immunoglobulins
- Transport proteins
- Acute-phase proteins
- Immunoglobulins
Total protein reflects:
- Protein synthesis (liver)
- Protein loss (kidney, gut)
- Hydration status
- Inflammatory and immune activity
It is a screening test, not disease-specific, and should always be interpreted with albumin and globulin levels.
Physiological Role
Plasma proteins are essential for:
- Maintaining oncotic pressure
- Transport of hormones, drugs, metals
- Immune defense (antibodies)
- Blood clotting
- Buffering acid–base balance
Clinical Significance
LOW TOTAL PROTEIN
Common Causes
1. Decreased Synthesis
- Chronic liver disease
- Cirrhosis
- Severe malnutrition
- Protein-energy malnutrition
2. Increased Loss
- Nephrotic syndrome
- Protein-losing enteropathy
- Severe burns
- Chronic diarrhea
3. Dilutional
- Overhydration
- Pregnancy
- IV fluid overload
Clinical Features
- Edema
- Ascites
- Muscle wasting
- Poor wound healing
HIGH TOTAL PROTEIN
Common Causes
1. Dehydration
- Vomiting
- Diarrhea
- Diuretics
2. Increased Globulins
- Chronic infections
- Autoimmune diseases
- Multiple myeloma
- Waldenström macroglobulinemia
- Chronic liver disease
Clues
High total protein with normal/low albumin → suspect hypergammaglobulinemia.
Reference Intervals
(Tietz 8E • IFCC • Mayo)
Serum Total Protein
- Adults: 6.0 – 8.3 g/dL
(= 60 – 83 g/L)
(= 6.0 – 8.3 g%)
(= 60 – 83 mg/mL)
Children
- Slightly lower in infants
- Approach adult levels by adolescence
Diagnostic Uses
1. Nutritional Assessment
Screening for protein deficiency.
2. Liver Disease Evaluation
Low total protein suggests impaired synthesis.
3. Renal Disease
Protein loss syndromes.
4. Plasma Cell Disorders
High total protein → evaluate with:
- Albumin
- Globulin
- A/G ratio
- Serum protein electrophoresis (SPEP)
5. Hydration Status
Dehydration falsely elevates total protein.
Analytical Notes
- Sample: serum or plasma
- Measured by Biuret method (standard)
- Lipemia and hemolysis can interfere slightly
- Always interpret with albumin
Clinical Pearls
- Normal total protein does NOT exclude disease - albumin and globulin may offset each other.
- Low albumin with normal total protein suggests increased globulins.
- High total protein with anemia → suspect plasma cell dyscrasia.
- In nephrotic syndrome, albumin falls more than total protein initially.
- Dehydration is the most common cause of mild elevation.
Interesting Fact
The Biuret reaction used to measure total protein is based on peptide bonds reacting with copper ions - the same principle discovered in the 19th century.
References
- Tietz Clinical Chemistry & Molecular Diagnostics, 8th Edition - Proteins
- IFCC Clinical Chemistry Standards
- Mayo Clinic Laboratories - Total Protein
- ARUP Consult - Protein Disorders
- MedlinePlus - Total Protein Test