A - CHAPTER III: PHLEBOTOMY Flashcards
1
Q
– collection of minute sample of blood through capillary puncture
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MICROSAMPLING
2
Q
INFANTS up to 1 year of age
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- Plantar surface of the big toe
- Median or lateral side of the heel
- Depth of puncture: up to 2.4 mm
3
Q
ADULTS:
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- Middle or ring finger
- Puncture must be slightly off-center, perpendicular to the fingerprint
- Margin of the earlobe
- Depth of puncture: up to 3.1 mm
4
Q
– collection of a greater volume of blood from the veins or arteries
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MACROSAMPLING
5
Q
ARTERIAL PUNCTURE:
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- Collection of arterial blood for blood gas analysis or blood pH determination
- Common sites: radial artery, brachial artery, femoral artery
6
Q
- Collection of venous blood
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VENIPUNCTURE
7
Q
Infants up to 18 months:
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External jugular vein
Superior longitudinal sinus
Temporal vein
8
Q
18 months to 3 years:
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Popliteal vein
Femoral vein
Long saphenous vein
Ankle vein
9
Q
3 years to adulthood:
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Veins on the antecubital fossa
Wrist vein
Veins on the dorsal of hands & feet
10
Q
3 years to adulthood:
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Veins on the antecubital fossa
Wrist vein
Veins on the dorsal of hands & feet
11
Q
METHODS OF PERFORMING VENIPUNCTURE:
A
I. OPEN SYSTEM
II. CLOSED SYSTEM
12
Q
– use of syringes
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OPEN SYSTEM
13
Q
- The hub of the needle is color-coded, corresponding to its gauge
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OPEN SYSTEM
14
Q
- The lower the gauge, the bigger the bore of the needle
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OPEN SYSTEM
15
Q
– use of an evacuated system (evacuated tube, two-way needle and adapter)
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CLOSED SYSTEM
16
Q
- Evacuated tubes are equipped with a hemogard (color-coded in accordance to the additive present)
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CLOSED SYSTEM
17
Q
- Multiple sampling can be carried out
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CLOSED SYSTEM
18
Q
– liquid portion of clotted blood
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SERUM
19
Q
– liquid portion of anti-coagulated blood
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PLASMA
20
Q
: preparation involves the removal of proteins from any biological specimen to prevent direct colorimetric interference by the formation of zwitterions at isoelectric pH where proteins exhibit maximum precipitation and minimum solubility
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PROTEIN-FREE FILTRATE (PFF)
21
Q
METHODS of PFF PREPARATION:
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A. Physical Methods:
1. Heat
2. Ultracentrifugation
B. Chemical Methods
(ACID Method)
1. Folin-Wu
2. Hayden’s method
3. Van Slyke
4. TCA (5%)
(BASE Method)
1. Nelson-Somogyi
22
Q
▪ Specimen: whole blood; plasma/serum
▪ 2/3 N Sulfuric acid
▪ 10% sodium tungstate
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Folin-Wu
23
Q
▪ Specimen: serum
▪ N/12 Sulfuric acid
▪ 10% sodium tungstate
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Hayden’s method
24
Q
- makes use of a pre-mixed acid
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Van Slyke
25
CONTAMINATION of SPECIMEN
❖ residual detergent in tubes
❖ Plasticizers in IV tubing and tube stoppers
❖ Cork stoppers & glass tubes
❖ Lead analysis: use lead-free, acid-washed containers
26
Serum or plasma should be separated from cells [?] (unless collected in a gel separator tube).
within 2 hours of collection
27
Rate of glycolysis:
At ref temperature –
At room temperature –
2 mg/dL
7 mg/dL
28
Allow red top tubes to clot sufficiently (?) before centrifugation to avoid fibrin strands.
20-30 minutes
29
Centrifuge [?] at [?] × g.
10 ± 5 minutes
1000-1200
30
Keep tubes [?] during centrifugation
capped
31
can be ultracentrifuged
Lipemic specimens
32
SPECIMEN HANDLING REQUIREMENTS
33
• Patients should not eat or drink anything (NPO) except water
FASTING
34
• Glucose determination:
6 – 8 hours fasting
35
• Lipid Profile:
10 – 12 hours fasting
36
• Specimen to be collected at a specified time
TIMED
37
• Label the tube with the time the specimen was drawn
TIMED
38
• Tests for Cardiac profile
TIMED
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• Specimen collected when the highest serum concentration of a drug is anticipated
PEAK / Post-dose
40
• Drawn 30 minutes to 1 hour after administration of the drug
PEAK / Post-dose
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• Therapeutic Drug Monitoring
PEAK / Post-dose
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• Specimen collected when the lowest serum concentration of a drug is expected, usually before the next dose is administered
TROUGH / Pre-dose
43
• Chilling the specimen to slow down the metabolic process that will continue after blood is drawn
CHILLED
44
• Placed in crushed ice & water for even cooling
CHILLED
45
• Blood ammonia determination, blood gas analysis & Coagulation studies
CHILLED
46
• Keep specimen at body temperature or close to 37°C (incubator)
KEEP WARM
47
• For cold agglutinins
KEEP WARM
48
• Specimen should be wrapped in aluminum foil or a light-inhibiting container should be used
PROTECT FROM LIGHT
49
• Bilirubin, Vit. B12, Carotene
PROTECT FROM LIGHT
50
• For legal or forensic proceedings, sample may be used as piece of evidence
CHAIN OF CUSTODY
51
• Documentation of specimen handling begins with patient identification and continues until testing is complete
CHAIN OF CUSTODY
52
o It must include date, time and identification of handler, all to be done in the presence of a witness
CHAIN OF CUSTODY
53
• DNA Analysis, Drug testing, Alcohol levels
CHAIN OF CUSTODY
54
REASONS FOR SPECIMENT REJECTION
✓ Hemolysis
✓ Lipemic / Lactescent serum
✓ Clots in an anti-coagulated specimen
✓ Partially-filled tubes
✓ Improper transport conditions
✓ Discrepancies b/w requisition & specimen label
✓ Unlabeled or mislabeled specimen
✓ Contaminated specimen/Leaking container
55
SPECIMEN INTERFERENCES
1. HEMOLYSIS
2. ANTICOAGULANTS and PRESERVATIVES
3. ICTERIC SERUM / JAUNDICED SERUM
4. LACTESCENT SERUM / MILKY SERUM / TURBID SERUM
5. PARTIALLY-FILLED TUBES
6. SPECIMEN CONTAMINATION
56
o Destruction of RBCs result in a plasma or serum appearing pink to red
HEMOLYSIS
57
o Hemoglobin concentration: exceeds 200 mg/L
HEMOLYSIS
58
o In-vivo hemolysis
o In-vitro hemolysis
HEMOLYSIS
59
HEMOLYSIS Interferes with:
▪ Enzyme and electrolyte assays (K+, Zinc and Mg+2)
▪ Serum albumin (↑): Bromcresol Green method
▪ Serum protein (↑): Biuret method
▪ Serum bilirubin (↓): Diazo method
60
▪ Serum albumin (↑):
▪ Serum protein (↑):
▪ Serum bilirubin (↓):
Bromcresol Green method
Biuret method
Diazo method
61
o – dilution of plasma owing to water transport from the cells
Potassium oxalate
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o will inhibit various plasma enzyme activities
Anticoagulants that chelate calcium
63
o inhibit amylase activity
Oxalates or citrates
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o inhibit Lactate dehydrogenase and Acid phosphatase
Oxalates
65
will cause a decrease in calcium concentration
o EDTA, oxalates and citrates
66
Bilirubin interferes with the ff:
▪ Albumin assay:
▪ Cholesterol assay:
▪ Glucose determination:
▪ Total Protein determination:
HABA method
Ferric chloride reagents
ortho-toluidine method
Biuret method
67
LACTESCENT SERUM / MILKY SERUM / TURBID SERUM
o Interferes with the ff:
▪ Albumin assay:
▪ Calcium :
▪ Inorganic phosphates:
▪ CK, bilirubin and total protein levels decrease
▪ Inhibits the activity of
Bromcresol Green method
Cresolphthalein method
Ammonium molybdate
amylase, uricase and urease
68
For proper ratio of blood to anti-coagulant to be achieved, all tubes should be filled until
the vacuum is exhausted
69
Most important for Coagulation studies
PARTIALLY-FILLED TUBES
70
o Improper application of antiseptic on the site prior to venipuncture, or traces of Povidone iodine on the site of puncture
SPECIMEN CONTAMINATION
71
o Aseptic technique is very important for blood cultures.
SPECIMEN CONTAMINATION
72
o increases K+ and Uric acid
Iodine
73
SOURCES OF VARIATIONS IN SPECIMEN COLLECTION & PROCESSING
1. EXERCISE
2. PROLONGED FASTING
3. DIET
5. TOBACCO SMOKING6. POSTURE
6. POSTURE
7. OTHER FACTORS
74
immediate fall and then subsequent increase in the concentration of free fatty acids
Transient Effects
75
Increase in activities of muscle enzymes such as Creatine kinase, aldolase, AST, and Lactate dehydrogenase
Longer-lasting Effects
76
- Changes the levels of sex hormones
- During a six-month training, there is an increase in the mean plasma testosterone concentration by 21%, the androstenedione concentration by 25%
Long-term physical training
77
An 8 – 12 hour fasting is a must (GNFH or General Normal Fasting Hours) to ensure that laboratory measurements are compatible with reference values.
PROLONGED FASTING
78
- Increase in the plasma concentration of potassium and triglycerides
DIET
79
- Increase in plasma concentration of lactate, urate and the metabolites of ethanol namely acetaldehyde and acetate
ETHANOL INGESTION
80
- Up to 80% increase in carboxyhemoglobin
TOBACCO SMOKING
81
- Obtain specimen in a supine or upright sitting position
POSTURE
82
- Incorrect application of tourniquet, fist exercise cause an increase in the concentration of lactate, enzymes, proteins, protein-bound substances
OTHER FACTORS
83
DIURNAL VARIATION:
➢ Lower at night:
➢ Higher in the afternoon & evening:
• ACTH, Renin, Aldosterone, Insulin
• GH, ACP
84
peaks early to late morning & decreases during the day
Iron
85
SHOCK and TRAUMA:
➢ Increased:
cortisol, aldosterone, catecholamine, glucagon and insulin
86
affects adrenal hormone secretion.
Stress
87
will lead to disturbances in acid-base balance, an increase in the serum lactate concentration, and non-esterified fatty acids.
Anxiety resulting in hyperventilation
88
an increase in the serum lactate concentration
acid-base balance
89
SKIN COLOR:
➢ Blacks have increased
CK, aldolase, and LDH
90
MENSTRUAL CYCLE:
➢ Increased
cholesterol, protein, albumin, fibrinogen, Mg, Cl-, Na+, and PO4
