Lec 8: Specimen Collection Flashcards
Neonatal screening filter paper is usually done ___.
1 to 2 days after birth
- Serum is much clearer because of ___.
- Plasma is somewhat hazy because of ___.
- Absence of fibrinogen
- Presence of fibrinogen
Used in microbiology and can cause false increase in P, Uric avid, and K.
Cleaning agent: betadine (povidone iodine)
How is blood collection performed when collecting from an IV site?
• Above IV should be avoided
• Collect from below the IV after it is turned off for 2 to 5 minutes
• discard the first 5mL
Tourniquet application for ___ minutes increases __, Iron, ___, and __.
(a) more than 3 minutes
(b) TP, AST bilirubin, total lipids
ANTICOAGULANT INTERFERENCE
- Inhibits amylase
- Action of Fluoride
- Chelates metallic enzyme activators
- Action of Oxalate
- Oxalate & Citrate
- Inhibits enzyme activity
- EDTA
- Inhibits amylase, LD, & ACP
- characterized by a milky or highly turbid serum
- obtained normally after a meal due to elevated exogenous chylomicrons
Lactescence (Lipemic serum)
Intensely yellow serum due to elevated bilirubin
Ictericia (icteric serum)
- Leakage of intracellular substance is called ___.
- Common causes of IN VITRO hemolysis
- Laking
- In vitro causes:
• Vigorous mixing
• alcohol
• too narrow/wide needle bores
• under draw & did not hit vein
• centrifuge before blood completely clots around 20-30 minutes
Sites for skin puncture
- free edges earlobe
- palmar surface of finger
- plantar surface of heal & toe
In skin puncture, the depth of the incision should be ___ to avoid contact with bone
Less than 2.5 mm
A suitable substitute for arterial blood determination of pH & pCO2
Capillary blood
• when warmed, blood flow increases, so it becomes arterial-rich blood
Complications of Arterial puncture
- hematoma
- blood flow restriction
- temporary discomfort
- thrombosis, hemorrhage, infection
ARTERIAL PUNCTURE
- Preferred sites
- Anticoagulant used
- Needle sizes used
- Angles in collection
- Brachial & Radial arteries
- Heparin
-
(a) Radial: 23–25
(b) Brachial: 18–20 -
(a) Brachial: 45–60°
(b) Femoral: 90°
A swelling or mass of blood that can be caused by blood leaking from a blood vessel during or following a venipuncture
Hematoma
COMPLICATIONS OF VENIPUNCTURE
- Local immediate
- Local delayed
- General delayed
Local immediate
• Hemoconcentration
• failure of blood to enter syringe
• syncope
• circulatory failure
Local delayed
• Hematoma
• Thrombophlebitis
• thrombosis
General delayed
• HIV
• Hepatitis B
Anticoagulant
- prevents glycolysis
- shows abnormal cell morphology
- for glucose test, blood alcohol, and lactic acid
Gray top tube
✓ Sodium Fluoride
• prevents glycolysis
✓ Potassium oxalate
• anticoagulant
Anticoagulant
- chelates and decreases calcium and iron
- anticoagulant of choice of Hematology
- for CBC & forward blood typing
Lavender top tube
✓ EDTA
Anticoagulant
- causes least interference
- inhibits thrombin & factor 10 A
- for blood gases, electrolytes, NPN
Green top tube
✓ Lithium heparin
✓ Sodium heparin
✓ Ammonium heparin
- Anticoagulant of Gold Top tube
- Anticoagulant of Red top tube (plastic)
- Lab test for Red top tube
- Anticoagulant of Light blue top tube
- Purpose of Light blue top tube
- Purpose of Yellow top tube
- Anticoagulant of Yellow top tube
- Silica with thixotropic gel
- Silica
- Serology, cross matching, reverse blood typing
- Sodium citrate
- Coagulation studies
- Microbiology/blood culture
- SPS
Inert substances contained in/near the bottom of tubes which lodges between cell and fluid — forming a barrier
Gel / Thixotropic gel separators
- Hastens the clotting to extract serum faster
- ex: thrombin
Clot activators
Gauge of:
- Green
- Blue
- Black
- 21
- 23
- 22
Tests must be done on the specimen not longer than ___ from blood collection
2 hours
Angle of venipuncture
15°
Application of tourniquet must be ___ the site. It must not be applied more than ___.
(a) 2 to 3 inches above
(b) 1 minute
SITES OF VENIPUNCTURE
- often the only vein felt in obese patients
- Not well anchored and rolls easily
- Large, most stationary and closer to the surface
- Cephalic vein
- Basilic vein
- Median cubital vein
Blood specimen
- Contains arterial and venous blood
- Lower oxygen, dark bluish color
- Rich in oxygen, bright red color
- Capillary blood
- Venous blood
- Arterial blood
Specimens that are anaerobic and are placed in ice slurry
Lactic acid, ammonia, blood gas
- In vivo common interferences
- In vitro common interferences
In Vivo
• dehydration
• ethanol ingestion
• lifestyle
• tobacco smoking
In vitro
• hemolysis
• platelets
• position
• microclot