1. ·        Lecture 33& 34 : Specimen collection and processing -1
ط      Blood specimen types
ط     Venipuncture , procedure, precautions
ط     Pediatric venipuncture
ط     Skin puncture, arterial puncture
                                               B3  39-50;  C4   40 -  2

2. Introduction
Proper patient identification, correct equipment, adequate knowledge (physiological & environmental factors)
Proper collection (sample type, timely), transport, processing, analysis, reporting
Previous chain is critical in providing most accurate clinical picture (weakest link)
Added investment of time & effort for patients care & management of specific group
Pediatric, obese, elderly, ICU, women?

3. Blood Specimen Types:
Blood is most common specimen (Whole, serum, plasma)
Blood can be obtained from veins, arteries, capillaries
1. Arterial blood is commonly used for blood gases & pH
2. Venous blood content varies depending on metabolic activity of tissue (time / site)
3. Capillaries (veins & arteries)

4. Blood Specimen Types:
1. Arterial blood is commonly used for blood gases & pH
O2 is the largest difference
Reflects the respiratory & metabolic status
Others are protein, glucose, ammonia
Limited to some conditions
Collected & performed by trained personnel

5. Blood Specimen Types:
2. Venous blood content varies depending on metabolic activity of tissue (time / site)
Timing & site of collection are critical
Obtained by venipuncture
Institute standardize collection, location, patient positioning, tourniquets

6. Blood Specimen Types:
3. Capillaries (veins & arteries)
Obtained by skin puncture
Similar to venipuncture: high glucose, low K, total protein, Ca++
Also contain intracellular & tissue fluids
Used if venous is not accessible:
Burns, chemotherapy, difficult veins (obese, elderly), risk of collapse (infants)
Warming of site causes increase blood flow
=> lead to vasodilation => result in arterialization of capillaries
Excessive squeezing result in increase of K

7. Venipuncture
1. evacuated-tube (vacutainer)
Sample is completely contained to
reduce risk of outside contaminant
reduce hazards on the collector
2. Syringe collection
necessary when patient has fragile or damage veins
3. Butter-fly infusion
more expensive but convenient when both vacutainer tubes & syringe collected at the same time
used mostly on pediatric patients, difficult veins

8. Tourniquet
Belt or rubber or tubing used to apply venous pressure
NO prolonged pressure
For convenient & comfortable collection

9. Needles
Bore size referred as gauge
Larger needles (18 gauge) used for blood donors
Smaller needles (21-22) used in routine collection
Smallest needles (23-25) used with butterfly infusion, could cause hemolysis
1. single-sample needle: collecting with a syringe
2. multiple-sample needle:
allow tube change without blood leakage (vacutainers)
plastic sleeves with stopper: differ is size depending on manufacturer

10. Tubes
Colour-coded stopper indicating additive present
preservatives, anticoagulants, accelerators, plain

11. Others
1. Alcohol pads:
to sterile site of puncture
iodine used for blood culturing
2. Gauze:
can use folded cotton gauze
3. Tape or adhesive bandage
avoid in under 3 years old

12. site of venipuncture
antecubical fossa most common, arm (median cubical vein)
other sites are acceptable: hand, ankle, foot
avoid collecting from: hematomas, scarring, previous puncture, mastectomy side, IV fluid site

13. Procedure of venipuncture
From 1 to 20 on page 49

14. Pediatric venipuncture
Hazard include: cardiac arrest, hemorrhage, venous thrombosis, arterispams, tissue damage, infection
Use butterfly (21-23 gauge), 3ml syringe (tube)
Collect only form superficial veins, secure arm, no bandage for under 3 years

15. Precautions during venipuncture
Fainting, nausea, vomiting
STOP immediately
Head lowered, cold compression, ammonia, physician

16. Skin Puncture
Blood is brought to the surface of the skin by applying pressure to the site (infants)
Alcohol pads used to sterile
Lancet with controlled depth (2.4mm) to avoid abscess, bruises, bone damage ..
Microcollection Tubes (additives are powder, freeze dried)
Silican separator gel (separate liquid from cell components)
Heel warmer, no more than 42ºC

17. Site of skinpuncture
Finger: palmer surface, 3-4rd ring finger
Heel: middle of the large toe to heel

18. Procedure of skinpuncture
From 1 to 17 on page 53-54

19. ·        Lecture 35& 36 : Specimen collection and processing-2
ط     Anticoagulants : mechanisms and uses
ط     Preservation and transport
ط     Factors affecting specimen collection, Sources of error,
                                           B3  50-58;  C4   40 -  2

20. Additives Table 3.3
No additives (red, dark-blue) for blood culturing, then
Sodium-citrate (light-blue) for coagulation studies followed by
Heparin (green) for electrolyte then
EDTA (lavender) for hematology and
oxalate / fluoride (gray) for glucose

21. Specimen Transport
Upon receiving in the lab, information should be matched and read correctly and accepted
Then sorted as to type of test and distributed to the lab unit
As soon as collected & quick as possible if no metabolic inhibitors present
Avoid common problems as hemolysis
Primary & secondary leak-proof containers
Ice to maintain integrity of analytes
Remove serum within 1hr of centrifugation & centrifuge max 60 min after collection
Maintained in upright position, to promote clot & reduce hemolysis
Temp 23-25ºC preferred
Personnel aware of handling requirement (cart, agitation, delay)
Some require chilling to inhibit metabolism (tube)
Certain tests require avoiding light (dark tube)

22. Storage Stability
Serum / plasma should be separated from cell within 2hrs of collection
Analysis within 5hrs of centrifugation
Serum / plasma in gel separators can be stored at room temp 8-24hrs
Normally Storage at 2-8ºC up to 24hrs is acceptable for most analytes
Storage beyond 24hrs is by freezing – 20ºC (once)
Do NOT repeat freezing and thawing more than once
Some analytes need to be freezed immediately after separation

23. Factors affecting specimen Table 3.1
Timing:
Best time is early morning (basal state)
Time-intervals may be desired to observe metabolic process as glucose tolerance and serum iron and also in therapeutic drug monitoring
Diet:
physicians must not if diet restriction is require to phlebotomist
Fasting Specimen: diet high in protein, glucose, saturated & unsaturated FA, caffeine, serotonins
Exercise:
Moderate exercise can affect certain values
Stress:
Emotions may falsely elevate white blood cells
Pasture:
Body diurnal rythms and pasture (sitting or laying)
Hemolysis & Tourniquet
** For forensic collection (law & medicine) in the presence of officer

24. Sources of error in venipucture
Table 3.5
Table 3.6

25. Other body fluids
1. Cerebral Spinal Fluid:
Obtained by lumber puncture
For glucose, total & specific protein determination, pH, CO2, bicarbonate
2. Paracentess Fluid (pleural, pericardial, peritoneal):
Collected by aspiration of site
For specific gravity, protein, LDH determination
Collect blood sample in conjunction
3. Amniotic Fluid:
Obtained by aspiration of fetus amniotic sac
For fetal lung maturity, congenital diseases, hemolytic anemia, neural tube defect, gestational age
4. Urine:
A. Random (first void): for protein, glucose, specific gravity, osomlility,
Dark-colored contained for some test (e.g. bilirubin)
B. Timed (12-24hrs/befor or after a meal):
Low electrolyte, catecholamine in morning then peak at noon
Preservatives (acid/base/refrigeration) used in certain analytes and bact. growth