How much edta required for 7.5 ml blood and how much serum did we get from this blood
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Here are the answers to both your questions, based on authoritative laboratory medicine references:
EDTA Required for 7.5 mL Blood
EDTA is effective at a final concentration of 1–2 mg per mL of blood.
For 7.5 mL of blood:
- Minimum: 1 mg/mL × 7.5 mL = 7.5 mg EDTA
- Maximum: 2 mg/mL × 7.5 mL = 15 mg EDTA
- Standard/recommended: ~1.5 mg/mL × 7.5 mL = ~11.25 mg EDTA
Higher concentrations than 2 mg/mL will hypertonically shrink red blood cells (RBCs), causing morphological artefacts. — Tietz Textbook of Laboratory Medicine, 7th Ed.
The form used is typically K₂EDTA (spray-dried, preferred — does not dilute the sample) or K₃EDTA (liquid — dilutes sample ~1–2%).
Serum Yield from 7.5 mL of Whole Blood
Serum is obtained after blood clots and is centrifuged. Since serum lacks fibrinogen and clotting factors (which are consumed in clot formation), the yield is slightly less than plasma.
General rule: Serum yield ≈ 40–50% of whole blood volume
For 7.5 mL of whole blood:
- Expected serum = ~3.0–3.75 mL (roughly 3–4 mL)
This is because:
- Plasma constitutes ~55% of blood volume
- Serum is plasma minus the clot (fibrinogen + clotting factors), so approximately 40–45% of whole blood becomes usable serum
Note: EDTA tubes are used for plasma (not serum) — if you are using EDTA, you will get plasma, not serum. Plasma yield from EDTA tubes is slightly higher (~50–55% of blood volume), so from 7.5 mL: approximately 3.75–4.0 mL of plasma.
Summary Table
| Parameter | Value |
|---|---|
| Blood volume | 7.5 mL |
| EDTA required | 7.5–15 mg (ideal: ~11.25 mg) |
| Standard concentration | 1.5–2 mg/mL |
| Serum yield (red/SST tube) | ~3.0–3.75 mL |
| Plasma yield (EDTA/lavender tube) | ~3.75–4.0 mL |
Give the reading in ml of EDTA the above question
EDTA Required for 7.5 mL Blood — in mL
The standard EDTA solution used in laboratory tubes is 10% EDTA solution (i.e., 100 mg/mL), though some labs use a 15% solution.
Using 10% EDTA solution (most common):
Formula:
Volume of EDTA (mL) = [Blood volume (mL) × 1.5 mg] ÷ 100 mg/mL
= (7.5 × 1.5) ÷ 100
= 11.25 ÷ 100
= 0.1125 mL ≈ 0.112 mL
Practical Standard Rule:
The widely used clinical lab standard is:
1.5 mg EDTA per 1 mL of blood
| Blood Volume | EDTA (mg) | EDTA as 10% solution (mL) |
|---|---|---|
| 1 mL | 1.5 mg | 0.015 mL |
| 7.5 mL | 11.25 mg | ~0.112 mL |
In simple terms:
For 7.5 mL of blood, you need approximately:
0.112 mL (112 µL) of 10% EDTA solution
This is the volume routinely pre-filled in standard 3 mL or 5 mL EDTA (lavender top) vacutainer tubes scaled to the blood volume collected.
How much edta is required for how much blood in ml in pets
EDTA Requirements for Blood Collection in Pets (Veterinary)
The same core principle applies in veterinary medicine as in human medicine:
Standard ratio: 1.5 mg EDTA per 1 mL of blood
Common Pet Blood Tube Volumes & EDTA Required
| Animal | Typical Blood Collected | EDTA Required (mg) | EDTA as 10% solution (mL) |
|---|---|---|---|
| Dog | 1–3 mL | 1.5–4.5 mg | 0.015–0.045 mL |
| Cat | 1–2 mL | 1.5–3.0 mg | 0.015–0.030 mL |
| Rabbit | 0.5–1 mL | 0.75–1.5 mg | 0.0075–0.015 mL |
| Bird/Avian | 0.1–0.5 mL | 0.15–0.75 mg | 0.0015–0.0075 mL |
| Reptile | 0.3–1 mL | 0.45–1.5 mg | 0.0045–0.015 mL |
| Small rodents | 0.1–0.3 mL | 0.15–0.45 mg | 0.0015–0.0045 mL |
Standard Veterinary EDTA Tubes
| Tube Size | Blood Volume Intended | EDTA Pre-filled |
|---|---|---|
| 0.5 mL microtube | 0.5 mL | ~0.75 mg |
| 1.0 mL microtube | 1.0 mL | ~1.5 mg |
| 2.0 mL tube | 2.0 mL | ~3.0 mg |
| 3.0 mL tube | 3.0 mL | ~4.5 mg |
Key Points for Pets
- K₂EDTA (dipotassium EDTA) is the preferred form in veterinary practice — spray-dried, does not dilute sample
- Underfilling the tube is the most common error — excess EDTA relative to blood causes:
- RBC shrinkage/crenation
- Falsely low hematocrit (PCV)
- Platelet clumping artefacts
- Overfilling leads to inadequate anticoagulation and micro-clots
- For birds and reptiles, fill tubes to at least ½ capacity minimum due to small sample volumes
- Cats are especially prone to EDTA-induced platelet clumping — always mix gently by inversion (8–10 times)
Simple Formula
EDTA (mL of 10% solution) = Blood volume (mL) × 0.015
Examples:
- 1 mL blood → 0.015 mL EDTA
- 2 mL blood → 0.030 mL EDTA
- 3 mL blood → 0.045 mL EDTA
Amount of EDTA required for blood (blood transfusion)
Important Clarification First
EDTA is NOT used for blood transfusion storage.
EDTA only prevents clotting — it does not preserve red blood cells or provide nutrients for cell survival. Blood stored in EDTA deteriorates rapidly and is unsafe for transfusion.
Anticoagulants/Preservatives Actually Used in Blood Transfusion
1. CPDA-1 (Most Common — Standard Blood Bag)
Citrate + Phosphate + Dextrose + Adenine
| Component | Role |
|---|---|
| Citrate | Anticoagulant (chelates calcium) |
| Phosphate | Maintains pH, supports ATP synthesis |
| Dextrose | Nutrient/energy for RBCs |
| Adenine | Supports ATP resynthesis |
- Volume ratio: 63 mL CPDA-1 per 450 mL of blood
- Shelf life: Up to 35 days at 2–6°C
2. ACD (Acid Citrate Dextrose)
Used for blood banking and apheresis
| Formula | Ratio to Blood |
|---|---|
| ACD-A | 15 mL per 100 mL blood |
| ACD-B | 7.5 mL per 100 mL blood |
- Shelf life: Up to 21 days
3. CPD (Citrate Phosphate Dextrose)
- 63 mL CPD per 450 mL of blood
- Shelf life: Up to 21 days
4. Additive Solutions (Extended storage)
Used with CPD/CPDA after plasma removal
| Solution | Shelf Life |
|---|---|
| AS-1 (Adsol) | 42 days |
| AS-3 (Nutricel) | 42 days |
| AS-5 (Optisol) | 42 days |
Where EDTA IS Used in Transfusion Medicine
EDTA is used only for pre-transfusion testing (compatibility testing), not storage:
| Use | Tube | Volume |
|---|---|---|
| ABO grouping | Pink top (K₂EDTA) | 3–5 mL blood |
| Rh typing | Pink top (K₂EDTA) | 3–5 mL blood |
| Crossmatch / antibody screen | Pink top (K₂EDTA) | 3–5 mL blood |
| Direct Coombs test (DAT) | EDTA tube | 3–5 mL blood |
EDTA pink-top tubes are FDA-approved specifically for blood bank/transfusion testing. Standard ratio: 1.5 mg EDTA per 1 mL blood
Summary
| Purpose | Anticoagulant Used | EDTA Used? |
|---|---|---|
| Blood transfusion storage | CPDA-1 / CPD / ACD | ❌ No |
| Pre-transfusion testing | K₂EDTA (pink top) | ✅ Yes |
| Routine CBC/hematology | K₂EDTA (lavender top) | ✅ Yes |
| Coagulation tests | Sodium citrate (blue top) | ❌ No |
If you are asking about a specific scenario (e.g., veterinary transfusion, autologous donation, apheresis), let me know and I can give more targeted information.
How to calculate the blood transfusion required for cat and dog
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The library doesn't carry veterinary-specific texts, so here is a comprehensive answer from established veterinary clinical practice:
Blood Transfusion Volume Calculation in Dogs & Cats
Standard Formulas
For DOGS
Formula 1 — Most Commonly Used (PCV-based):
Volume (mL) = Body weight (kg) × 90 × [(Target PCV − Patient PCV) ÷ Donor PCV]
- 90 mL/kg = estimated blood volume of dogs
- Target PCV is usually 25–35% (depending on clinical signs)
Example:
- Dog: 10 kg, Patient PCV = 12%, Target PCV = 25%, Donor PCV = 45%
- = 10 × 90 × [(25 − 12) ÷ 45]
- = 900 × [13 ÷ 45]
- = 900 × 0.289
- = ~260 mL whole blood
For CATS
Formula (Same structure, different blood volume):
Volume (mL) = Body weight (kg) × 70 × [(Target PCV − Patient PCV) ÷ Donor PCV]
- 70 mL/kg = estimated blood volume of cats
- Target PCV is usually 20–25%
Example:
- Cat: 4 kg, Patient PCV = 10%, Target PCV = 20%, Donor PCV = 40%
- = 4 × 70 × [(20 − 10) ÷ 40]
- = 280 × [10 ÷ 40]
- = 280 × 0.25
- = ~70 mL whole blood
Quick Reference Formula (Simplified)
If donor PCV is unknown or assumed standard (~40–45%):
| Species | Quick Estimate |
|---|---|
| Dog | 2 mL/kg raises PCV by ~1% |
| Cat | 2 mL/kg raises PCV by ~1% |
Blood Volume Constants
| Species | Estimated Total Blood Volume |
|---|---|
| Dog | 80–90 mL/kg (use 90 mL/kg) |
| Cat | 60–70 mL/kg (use 70 mL/kg) |
For Packed Red Blood Cells (pRBC) Instead of Whole Blood
Volume pRBC (mL) = Body weight (kg) × Blood volume (mL/kg) × [(Target PCV − Patient PCV) ÷ PCV of pRBC unit]
- PCV of pRBC unit is typically ~70–80%
Dog Example (pRBC):
- 10 kg dog, Patient PCV = 12%, Target = 25%, pRBC PCV = 75%
- = 10 × 90 × [(25−12) ÷ 75]
- = 900 × 0.173
- = ~156 mL pRBC
Administration Rate
| Situation | Rate |
|---|---|
| Stable patient | 2–4 mL/kg/hr |
| Moderate anemia | 5–10 mL/kg/hr |
| Emergency/acute blood loss | Up to 20–22 mL/kg/hr (dogs), 10 mL/kg/hr (cats) |
| Maximum safe volume (cats) | Do not exceed ~50–60 mL total per transfusion event |
Transfusion Trigger (When to Transfuse)
| Species | PCV Threshold | Clinical Signs |
|---|---|---|
| Dog | PCV < 20% (acute), < 15% (chronic) | Tachycardia, weakness, pale mucous membranes |
| Cat | PCV < 15% (acute), < 12% (chronic) | Lethargy, open-mouth breathing, collapse |
Summary Card
| Parameter | Dog | Cat |
|---|---|---|
| Blood volume constant | 90 mL/kg | 70 mL/kg |
| Formula | BW × 90 × (Target−Patient PCV)/Donor PCV | BW × 70 × (Target−Patient PCV)/Donor PCV |
| Target PCV | 25–35% | 20–25% |
| Max single transfusion | No strict limit | ~50–60 mL |
| Admin rate (stable) | 2–4 mL/kg/hr | 2–4 mL/kg/hr |
Always monitor the patient during transfusion for reactions: urticaria, vomiting, fever, hypotension, or dyspnea — stop immediately if these occur.
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