How to Blood Letting for Medical Testing

Confirm patient identity using two identifiers and assemble all necessary blood collection equipment with proper labeling verification. Example: Check patient's full name and date of birth against requisition form and have patient state their information verbally, verify collection tubes match ordered tests including additives like EDTA for CBC, sodium citrate for coagulation studies, or serum separator tubes for chemistry panels, inspect tube expiration dates and ensure vacuum integrity by checking for proper seal and absence of cracks, prepare collection area with alcohol prep pads, gauze, tape, and bandages within easy reach, label collection tubes with patient information including name, DOB, collection date and time before beginning procedure, review any special collection requirements such as fasting status, specific collection times, or temperature sensitive specimens, check for patient allergies to antiseptics or adhesives that might affect collection process, and ensure proper lighting and comfortable positioning for both patient and phlebotomist to minimize collection errors.

Position patient comfortably and systematically locate the best available vein for blood collection using proper assessment techniques. Example: Seat patient in phlebotomy chair with arm extended and supported on armrest at heart level to optimize venous filling, examine antecubital fossa starting with median cubital vein as first choice due to size and stability, palpate potential veins using index finger to assess depth, direction, size, and resilience avoiding areas with scars, bruises, or previous hematomas, consider alternative sites like cephalic or basilic veins if median cubital is not suitable, noting that basilic vein is closer to brachial artery and requires extra caution, warm the arm with warm towel or have patient make fist several times if veins are difficult to locate, avoid areas with tattoos, IV sites, mastectomy side, or areas with skin infections that could compromise collection safety, use vein finder device for challenging cases with deep or small veins particularly in pediatric, elderly, or dehydrated patients, and select 21-gauge needle for routine adult collections or 23-gauge for smaller veins while avoiding larger gauges that may cause hemolysis.

Apply tourniquet properly to engorge target vein and execute venipuncture using sterile technique with appropriate needle angle and insertion method. Example: Place tourniquet 3-4 inches above intended puncture site and tighten until radial pulse is still palpable but venous return is restricted, clean venipuncture site with antiseptic using circular motion from center outward and allow to air dry for 30 seconds to ensure maximum antimicrobial effect, anchor vein below puncture site using non-dominant thumb while stretching skin taut to prevent vein rolling during needle insertion, insert needle bevel-up at 15-30 degree angle in direction of blood flow with smooth confident motion until flash of blood appears in needle hub, advance needle slightly into vein lumen then hold steady while attaching collection tube to evacuate blood, maintain needle position throughout collection process and avoid excessive manipulation that could damage vein wall or cause hematoma formation, monitor patient for signs of vasovagal reaction including pallor, diaphoresis, or dizziness throughout procedure, and ensure tourniquet time does not exceed 1 minute to prevent hemoconcentration affecting lab results.

Collect multiple blood samples following established tube sequence to prevent cross-contamination of additives between different collection tubes. Example: Follow standard order of draw starting with blood culture bottles if ordered, then coagulation tubes (light blue), serum tubes (red or gold), heparin tubes (green), EDTA tubes (purple), and glycolysis inhibitor tubes (gray) last, fill each tube to proper capacity indicated by fill line to ensure correct blood-to-additive ratio for accurate test results, gently invert tubes containing additives immediately after collection using 8-10 gentle inversions to mix blood with preservatives without causing hemolysis, change tubes smoothly without moving needle position by using tube holder that allows safe tube exchange, remove tourniquet before removing final tube or after 1 minute maximum to prevent specimen concentration, monitor tube vacuum and switch to new needle if flow becomes sluggish indicating possible clot formation or needle obstruction, keep filled tubes at room temperature or follow specific storage requirements for temperature-sensitive tests, and maintain steady needle position throughout multiple tube collections to prevent patient discomfort and vein damage.

Safely remove needle using proper technique and apply appropriate pressure to achieve complete hemostasis at puncture site. Example: Place clean gauze over puncture site before needle removal to immediately absorb any blood and provide pressure point, activate needle safety mechanism if using safety-engineered devices and remove needle in smooth motion at same angle as insertion, apply firm direct pressure to puncture site for minimum 3-5 minutes or longer if patient takes anticoagulant medications, instruct patient to keep arm straight and avoid bending elbow which can reopen puncture site and cause bleeding, check for complete hemostasis before applying bandage by briefly lifting pressure and ensuring no active bleeding continues, avoid applying bandage over wet blood which can compromise adhesion and provide inadequate pressure, dispose of needle immediately in approved sharps container without recapping to prevent needlestick injuries, observe puncture site for hematoma formation which appears as localized swelling and discoloration around collection site, and provide patient with post-collection instructions including keeping bandage on for 15 minutes and avoiding heavy lifting with collection arm for remainder of day.

Process collected specimens according to laboratory requirements and complete all necessary documentation for proper chain of custody and test processing. Example: Verify all specimen labels match patient identification and requisition information including correct spelling of name, date of birth, and collection date/time, transport specimens to laboratory according to specified temperature and timing requirements with some tests requiring immediate processing while others are stable at room temperature, complete collection documentation including any difficulties encountered, number of attempts required, or patient reactions during procedure, note any deviations from standard protocol such as alternative collection sites, patient positioning modifications, or special handling requirements, store specimens properly with some requiring refrigeration, others needing room temperature, and certain tests demanding immediate centrifugation, maintain chain of custody documentation if required for legal or forensic specimens including signatures and times of transfer, monitor patient briefly after collection to ensure no delayed vasovagal reactions or continued bleeding from puncture site, and schedule follow-up collections if serial monitoring is required for specific tests or if initial collection was insufficient for all ordered tests.