Vacutainers (Blood Collection Tubes)

Vacutainers (Blood Collection Tubes)

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Color
Common Name
Anticoagulant / Additive
Key Uses
Mixing
Mnemonic/Notes
Light Blue
Citrate Tube
3.2% trisodium citrate
Blood:Anticoagulant
• Coagulation studies 
→ Ratio 9:1
3-4 times
3.8% trisodium citrate for ESR 
(Westergren)
→ Ratio 4:1

Black cap
Red
Serum Tube
Clot activator 
(silica)
Obtain serum
Clotting: 60 mins.
5-6 times
Serum Separator Tubes (SSTs)
Yellow (Gold)
SST
Clot activator + Gel separator
Obtain serum
Clotting: 30 mins.

Can be transported and stored → gel do not allow mixing of cells and serum →
5-6 times
Serum Separator Tubes (SSTs)
Light Green
Heparin
Lithium Heparin (Li)
Heparin - 0.05 mL
ABG analysis

Quick biochemical analysis

Molecular diagnostic and cytogenetics
~8 times
Har reminds of Heparin
Dark Green
Heparin
Sodium Heparin (Na)
‘’
~8 times
Har reminds of Heparin
Purple/Lavender
EDTA
K2 EDTA
Routine tests:
CBC,
peripheral smear,
reticulocyte count,
ESR (Wintrobe tube), 
Glycated Hemoglobin (HbA1c)

Labile Parameters
• Ammonia
• PTH
• ACTH
~8 times
"Bread and butter of pathology"; HbA1c because hemoglobin
Gray
Glucose Tube
Potassium oxalate 
(Anticoagulant), 
Sodium fluoride 
(Additive)
All Glucose tests 
except HbA1c
~8 times
G for Gray, 
G for Glucose;
Sodium fluoride ⛔ enolase (prevents glycolysis).
Pearly White
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K2 EDTA
PCR samples
~8 times
P for Pearly white, P for PCR
Royal Blue
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K2 EDTA or None
Rare trace elements 
(copper, zinc)
~8 times
From mnemonic below
Pink
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K2 EDTA
Blood banking samples 
(e.g., cross-matching, denotes sensitivity)
~8 times
From mnemonic below
Tan
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K2 EDTA
Suspected lead poisoning
~8 times
Tan reminds of tin and lead
Black
ESR Tube
Trisodium citrate 
(often 3.8%)
Automated ESR estimation
Varies
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Orange
Rapid Serum Tube
Thrombin (clot activator)
Rapid serum collection
Clotting: 5 mins.
5-6 times
Serum Separator Tubes (SSTs)
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Serum vs Plasma

  • Serum
    • Obtained after blood clots d/t Negative charge of collecting tube
    • So has no clotting factors
  • Plasma
    • Has clotting factors including fibrinogen
    • Blood is collected in a tube with anticoagulant (K2EDTA) → Blood cells are also present → Lavender tube → K2EDTA causes → Hyperkalemia, Hypocalcemia (give falsely low electrolytes and enzyme activities)
  • Mnemonic:
    • Light Blue → Blue mojito → Citrate
    • Red → Blood → Clot
    • Yellow → yellow jelly → gel → clot
    • Green → Green Gall bladder → Liver → Heparin
    • Grey → Greys anatomy le oruthan
      • Panjara (Glucose except HbA1C) Pottan (Pottassium oxalate anticoagulant)
      • Addicted to Soda (sodium fluoride additive)
    • EDTA → Eduthaath
      • Royal (Royal blue) Pearl (Pearly white)
        • Royal (royal blue) is rare → Trace elements
        • Pearl (pearly white) → PCR (p for p)
      • Pink (Pink) Bra (Blood bank)
      • Purple (Lavender) Tin (Tan)
        • Lavender → HbA1c, ESR wintrobe, CBC
        • Tin → Tan → Lead

Measurement of PCV and ESR:

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Wintrobe tube
Westergren pipet
Automated ESR
Tube
Small
Long
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Measures
PCV and ESR
Only ESR
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Rob both PCV and ESR
WEST → ESR → Only ESR
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Vacuntainer
Lavender
Light blue
Black
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Lovely Wind
Western blue
Black Auto
  • Light Blue
    • ESR → 4:1
    • APTT/PT/INR → 9:1
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Order of Blood Draw:

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  • Mnemonic: "Stop light is red, red, yellow, green, green light says go"
      1. Sterile Bottle or Yellow bottle (Microbiology culture).
      1. Light Blue (3.2% trisodium citrate).
      1. Red (Serum separator).
      1. Yellow (SST - Serum separator with gel).
      1. Green (Heparin).
      1. Light (Lavender/Purple - EDTA).
      1. Gray (Glucose - Fluoride/Oxalate).

Glycated Haemoglobin (HbA1C)

  • Measures
    • Irreversible
    • non-enzymatic glycation of
    • N-terminal Valine of the
    • beta globin chain of
    • Adult Haemoglobin.
  • Reflects long-term glycemic status (latest 6-8 weeks).
  • Unaffected by short-term changes or enzymatic activity.
    • Due to 120-day lifespan of RBCs.
  • Estimation Methods
    • Ion exchange Chromatography
      • Most used, standard technique
    • Affinity Chromatography,
    • Electrophoresis,
    • Immunoassays.

Limitations of HbA1C

  • Iron deficiency anemia:
    • RBC lifespan is prolonged.
    • Falsely elevated HbA1C.
  • Hemolytic anemia:
    • RBC lifespan is reduced.
    • Falsely decreased HbA1C.
  • In such cases, Fructosamine can be used.

Fructosamine

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  • Irreversible non-enzymatic glycation of Albumin.
  • Not affected by RBC lifespan.
  • Provides glycemic status for the last 3-4 weeks.
  • Fructosamine is a protein (Albumin)
  • Immunoassays are used for its estimation.