Comprehensive Notes on Blood Collection Equipment, Additives, and Order of Draw

Blood Collection Equipment, Additives, and Order of Draw

Overview

This chapter covers equipment, additives, and order of draw crucial for blood collection.
It aligns with the GMEC CPT Study Guide for the National Certification Exam.
Objectives include understanding equipment, supplies, evacuated tube system (ETS), syringe system components, blood collection additives, and ETS tube stopper color coding.
NAACLS Entry Level Competencies are addressed.

General Blood Collection Equipment and Supplies

Blood-Drawing Station: Includes a table for supplies, a special chair, and a bed or reclining chair.
Phlebotomy Chairs: They should be comfortable and have adjustable armrests.
Phlebotomy carts: Keeping carts and trays adequately stocked with supplies is an important duty of the phlebotomist.
Gloves and Glove Liners:
- Required by CDC/HICPAC & OSHA when performing phlebotomy.
- A new pair must be used for each patient & removed when done.
- Acceptable materials: Nonsterile, disposable latex, nitrile, neoprene, polyethylene, & vinyl.
- A good fit is essential.
- Glove liners may be used if gloves cause allergies or dermatitis.
- Barrier hand creams can help prevent skin irritation from gloves.
- Gloves with powder are not recommended.
Antiseptics:
- Prevent sepsis (microorganisms or their toxins in the blood).
- 70% isopropyl alcohol is most common for routine blood collection.
- Safe on human skin.
Disinfectants:
- Remove or kill microorganisms on surfaces & instruments.
- Not safe on human skin.
Hand Sanitizers:
- Alcohol-based rinses, gels, & foams.
- Can replace handwashing if hands are not visibly soiled.
- Decontamination of hands after glove removal is essential because any type of glove may contain defects, and some studies suggest that vinyl gloves may not provide an adequate barrier to viruses.
Gauze Pads:
- Clean 2 × 2-in gauze pads folded in fourths are used to hold pressure over site following blood collection.
- Some pads have fluid-proof backing to prevent contamination.
- Avoid using cotton balls, as they tend to stick.
Bandages:
- Used over blood collection site once bleeding has stopped.
- Can also use paper, cloth, or knitted tape over folded gauze.
Slides
Pen
Watch
Patient identification equipment
Needle & sharps disposal containers & biohazard bags

Venipuncture Equipment

Vein-Locating Devices:
- Transillumination: shine high-intensity LED or infrared light.
- Highlights veins in patient’s subcutaneous tissue.
Tourniquet:
- Device applied or tied around patient’s arm to restrict blood flow.
- Should restrict venous flow to inflate veins, but not arterial flow.
- Most common type: stretchable disposable straps.
Needles:
- Sterile, disposable, designed for single use only.
- Types: Multisample, Hypodermic, Winged infusion (butterfly).
- Parts: Bevel, Shaft, Hub, Lumen.
- Gauge:
  - Diameter of lumen.
  - Higher the gauge, the smaller the diameter of needle.
  - Appropriate range for phlebotomy: 20 to 23 (21 is most common).
  - Needles are color coded by gauge.
- Length:
  - 1- & 1.5-in lengths are most common for venipuncture.
Evacuated Tube System (ETS):
- Closed system in which blood flows through a needle inserted into a vein & then directly into a collection tube.
- Prevents exposure to air or outside contaminants.
- Allows numerous tubes to be collected with a single venipuncture.
- Components: Multisample needle, Tube holders, Needle & holder units, Evacuated tubes.
Multisample Needles:
- Allow multiple tubes to be collected in a single venipuncture.
- Double-pointed and have threaded part that screws into holder.
- Tube end of needle has retractable sleeve to prevent leakage.
- Available with and without safety features; if no safety feature, use with safety holder.
Tube Holders:
- With and without safety features; if no safety feature, use with safety needle.
Needle and Holder Units:
- Needle and holder permanently attached.
Evacuated Tubes:
- Used with both ETS & syringe method.
- Available in different sizes & volumes.
- Size used depends on: Age of patient, Volume of blood needed for test, Size & condition of patient’s vein.
- Available in glass & plastic (plastic preferred for safety).
- OSHA regulations require that the tube holder with needle attached be disposed of as a unit after use and never be removed from the needle and reused.
- Vacuum:
  - Negative pressure artificially created by pulling air from tube.
  - Designed to draw an exact volume of blood into tube.
- Additive tubes: substance added to tube (e.g., anticoagulant).
- Nonadditive tubes: no substance added to tube (rare).
- Stoppers: rubber or rubber with plastic covering.
- Color coding: color of stopper usually indicates type of additive.
- Expiration dates: for additive & vacuum, printed on tube label.
Syringe System:
- Alternative for patients with small or difficult veins.
- Syringe needles are 1- to 1.5-in long and must have a resheathing feature if used to draw blood.
- Syringes have a barrel and plunger.
Syringe transfer device: allows safe transfer of blood into tubes without using syringe needle or removing tube stopper.
Blood Collection Sets:
- Winged Infusion Set:
  - Commonly referred to as a butterfly.
  - Effective for small or difficult veins (hands; elderly & pediatric).
- Nonwinged Blood Collection Set:
  - VANISHPOINT: automated in-vein retraction to eliminate exposure.
Combination Systems:
- Complete system for blood collection.
- Blood collection tube & collection apparatus are combined in a single unit.
- Specimen can be collected by evacuated tube or syringe.
- Available with regular or butterfly-style needles.
- Safety devices are available.

Blood Collection Additives

Anticoagulants:
- Substances that prevent blood from clotting.
- Two methods of preventing clotting:
  - Precipitating calcium.
  - Inhibiting formation of thrombin.
- Types:
  - Ethylenediaminetetraacetic acid (EDTA).
  - Citrates.
  - Heparin.
  - Oxalates.
- Because the cells are free flowing and not clotted, a specimen collected in anticoagulant can separate through settling or centrifugation and can be resuspended by intentional or inadvertent mixing of the specimen.
- Anticoagulant specimens must be mixed immediately and gentle mixing prevents hemolysis. Numbers vary by manufacturer; consult manufacturer instructions for the recommendation for the number of inversions required.
- Light blue–top tubes: contain a 9:1 ratio of blood and must be filled to within 90% of that volume for accurate results. Vacuette® sodium citrate tubes have arrows that are used to identify correct fill volume.
Special-Use Anticoagulants:
- Acid citrate dextrose (ACD).
- Citrate phosphate dextrose (CPD).
- Sodium polyanethol sulfonate (SPS).
Antiglycolytic Agents:
- Substances that prevent glycolysis (breakdown of glucose by blood cells).
- Sodium fluoride (most common)
  - Preserves glucose for up to 3 days & inhibits bacterial growth.
  - Used w. potassium oxalate (anticoagulant) for rapid response.
Clot Activators:
- Substances that enhance coagulation in serum-separator tubes (SSTs).
- Types:
  - Substances that provide more surface for platelet activation:
    - Glass (silica) particles.
    - Inert clays (Celite).
  - Clotting factors (thrombin).
- Blood in an SST tube will eventually clot without mixing; however, when it is not mixed, glass particles may become suspended in the serum and could interfere in the testing process, as glass particles have been known to plug the small-diameter tubing in some analyzers.
Serum or Plasma Separator Tubes:
- Thixotropic Gel Separator
  - Has density between that of cells & serum or plasma.
  - When centrifuged, gel moves between cells & serum or plasma.
  - Prevents cells from continuing to metabolize substances.
- Trace Element-Free Tubes
  - Tubes made of materials free of trace element contamination
  - Used for trace element tests, toxicology studies, & nutrient determinations
  - Feature royal-blue stoppers

CLSI Order of Draw

Blood culture tube or bottles.
Sodium citrate tube.
Serum tube with or without gel.
Heparin tube with or without gel.
EDTA tube with or without gel separator.
Sodium fluoride/potassium oxalate glycolic inhibitor.

Carryover/Cross-Contamination:
- Transfer of additive from one tube to the next.
- Can occur when:
  - Blood in additive tube touches needle during ETS collection.
  - Blood is transferred from a syringe into ETS tubes.
- Order of draw presents a sequence of collection that minimizes risk for interference should carryover occur.
- Filling specimen tubes from bottom up minimizes carryover.
Tissue Thromboplastin Contamination:
- Tissue thromboplastin, present in tissue fluid:
  - Activates extrinsic coagulation pathway.
  - Can interfere with coagulation tests.
- For coagulation tests (other than PT or PTT), draw a few millimeters of blood into another tube before collecting coagulation specimen.
Microbial Contamination:
- Microorganisms found on skin can contaminate blood specimens.
- Blood cultures are collected first in order of draw, when sterility of site is optimal & to prevent contamination of needle.

NAACLS Entry Level Competencies Met in This Chapter

5. 00 Demonstrate knowledge of collection equipment, various types of additives used, special precautions necessary, and substances that can interfere in clinical analysis of blood constituents.
5. 1 Identify the various types of additives used in blood collection and explain the reasons for their use.
5. 2 Identify the evacuated tube color codes associated with the additives.
5. 3 Describe the proper order of draw for specimen collections.
5. 4 Describe substances that can interfere in clinical analysis of blood constituents and ways in which the phlebotomist can help to avoid these occurrences.
5. 5 List and select the types of equipment needed to collect blood by venipuncture and capillary (dermal) puncture.
5. 6 Identify special precautions necessary during blood collections by venipuncture and capillary (dermal) puncture.