Determining Hemoconcentration in Laboratory Samples
Measure serum total protein (STP) or albumin concentration, as protein levels below normal laboratory reference ranges indicate hemodilution, while elevated levels suggest hemoconcentration.
Primary Assessment Methods
The most practical and validated approach to detect hemoconcentration involves measuring protein concentration markers:
Serum Total Protein and Albumin
- Serum total protein (STP) serves as the most suitable parameter for calculating water content changes and detecting hemoconcentration 1
- Protein concentration shows excellent correlation with blood dilution status (r > 0.99) 2
- When protein levels fall below normal laboratory limits, the sample is hemodiluted; when elevated above normal, it indicates hemoconcentration 2
Hematocrit and Hemoglobin
- Hematocrit measurement remains the traditional standard for monitoring hemoconcentration, particularly in clinical contexts like dengue fever where plasma leakage occurs 3
- Hemoglobin concentration correlates strongly with hematocrit (r = 0.869) and can serve as an alternative marker 3
- Normal baseline values: hematocrit approximately 40-54%, hemoglobin 14-17 g/dL in healthy adults 4
- Increases of 2-4% in hematocrit or 0.7-1.0 g/dL in hemoglobin from baseline suggest hemoconcentration 1, 4
Practical Implementation
For Research and Biobanking Applications
Recent ISTH guidelines emphasize that measuring and reporting sample composition provides direct insight into potential confounders 5. This is particularly critical for:
- Extracellular vesicle research
- miRNA studies (where platelet contamination affects results)
- Multi-center studies requiring sample comparability
Quality Control Checkpoints
Monitor these parameters to ensure sample integrity 5:
- Platelet concentration (should be consistently low in plasma)
- Total protein levels
- Hemoglobin/hematocrit values
Common Pitfalls to Avoid
Do not rely solely on visual inspection of sample color or appearance, as this is subjective and unreliable 6. Instead:
- Always compare current values to baseline or reference ranges
- Account for the clinical context (exercise, stress, dehydration can cause physiologic hemoconcentration) 7
- In hemodiluted donors (those receiving ≥4 units of blood products within 48 hours), protein quantitation is essential before serologic testing to avoid false negatives 2
Correction for Hemoconcentration
If hemoconcentration is detected and you need to correct solute concentrations:
- Use baseline and current STP values to calculate the degree of plasma water loss 1
- Apply correction factors to eliminate the effect of hemoconcentration on measured analyte levels
- This is particularly important when comparing serial measurements or interpreting concentration-dependent assays