Specimen Collection and Processing

8/10/2019 Specimen Collection and Processing

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Maria Ruth B. Pineda, RMT, Ph.D.

Department of Medical Technology

University of Santo Tomas2

Objective and Scope

of Unit 4

Use standard protocol in handling and collecting specimen Promote ethical and social responsibilities in dealing with patients. Collaborate with other health care professionals for methods and protocols of specimen

handling and patient preparations needed for each determination. Communicate properly the laboratory procedures and requirements to patients and physicians.

1. Types of Specimen

1.1. Collection and Labeling

1.2. Handling, Transport processing, Storage, and Preservation

2. Specimen variables

2.1. Pre-collection

2.1.1. Patient identification and preparation2.1.2. Anticoagulants and preservatives

2.2. Collection

2.3. Post-collection

Types of Specimen

Body fluids: blood, CSF, urine, sweat, gastric juices, etc.

Tissues

Organs

Others: hair, nail, skin scrapings, etc.

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TYPES OF BLOOD SPeCIMEN

1. Serum

! liquid portion of clotted blood

! clearer than plasma

! with albumin and globulin but no fibrinogen

! not lipemic nor icteric

2. Plasma

! Liquid portion of unclotted blood

! with fibrinogen

3. Whole Blood

! plasma and red cells

! with anticoagulant4

3 ways of obtaining

blood specimen

1. Venipuncture

!

purplish venous blood

2. Arterial Puncture

! bright red arterial blood

!

used for ABG test

3. Skin Puncture

!

usually contaminated with tissues juices

! method of choice for pediatric and geriatric patients,extremely obese adults, severe burn patients, and those

with thrombotic tendencies (bleeding disorders)

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VEINS

Thinner walls than arteries

Collapse easily

Less pressure inside

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ARTERIES

Thick walls

Higher pressure: pulse

*no need to pull the plunger

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CAPILLARIES

One cell thick to allow exchange of gases

For micromethod collection only

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Tunica intima(endothelium)

Valve

Elastic tissue

Tunica media(smooth muscle)

Tunica adventitia(connective tissue)

Artery Vein

Capillary

Arteriole

Blood flow

Venule

FIGURE 2-1. Artery, vein, and capillary structure. (Reprinted with permission from McCall R, Tankersley C.

Phlebotomy essentials. 4th ed. Baltimore, Md.: Lippincott Williams & Wilkins, 2008.)

Venipuncture sites

1. Antecubital fossa

! Median cubital! Cephalic! basilic

2. Other veins

! Brachial! Femoral!

Radial

! Ankle veins

! Veins of the dorsalhand

!

Etc.10

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Basilic vein

Ant. mediancutaneous nerve

Post. mediancutaneous nerve

Brachialartery

Cephalicvein

Cephalicvein

Accessorycephalic

vein

Median cubitalvein

Medial cubitalnerve

Subclavianvein

Basilic vein

Median vein

A

CephalicveinBasilic vein

Dorsalmetacarpal

veins

C

Brachial artery

Cephalic vein

Cephalic vein

Accessorycephalic vein

Mediancephalic vein

Basilic vein

Ant. mediancutaneousnerve

Post. mediancutaneousnerve

Medialcubitalnerve

Subclavianvein

Median basilicvein

Basilic vein

Median vein

B

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Inappropriate

venipuncture sites

Arm on side of mastectomy

Edematous areas

Hematomas

Arm in which blood is being transfused

Scarred area

Arms with fistulas or vascular grafts

Sites above an IV cannula

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Skin puncture sites

lateral or at the medial surface of the heel

ring finger

ear lobes

How to puncture?

Clean the area

One quick deep stab

Perpendicular to the finger prints

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METHODS OF BLOOD

Collection based on amount

1.

Macromethod 1.0 mL and above

2. Micromethod 0.1 to 0.9 mL

3. Ultramicromethod 0.01 to 0.09 mL

4. Nanoliter method 0.001 to 0.009 mL

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Evacuated tubes

Tube Color and Anticoagulant/Additive

Stopper color Anticoagulant/additive Specimen type/use Mechanism of action

Red (glass) None Serum/chemistry and serology N/A

Red (plastic/Hemogard) Clot activator Serum/chemi stry and serology Sil ica clot activator

Lavender (glass) K3EDTA in liquid form Whole blood/hematology Chelates (binds) calcium

Lavender (plastic) K2EDTA/spray-dried Whole blood/hematology Chelates (binds) calcium

Pink Spray-dried K2EDTA Whole blood/blood bank andmolecular diagnostics

Chelates (binds) calcium

White EDTA and gel Plasma/molecular diagnostics Chelates (binds) calcium

Light blue Sodium citrate Plasma/coagulation Chelates (binds) calcium

Light blue Thrombin and soybean trypsininhibitor

Plasma/coagulation Fi brin degradation products

Black Sodium citrate Plasma/sed rateshematology Chelates (binds) calcium

Light green/black Lithium heparin and gel Plasma/chemistry Inhibits thrombin formation

Green Sodium heparin, lithium heparin Plasma/chemistry Inhibits thrombin formation

Royal blue Sodium heparin, K2E DTA P las ma /ch emi str y/ to xi co log y He pa ri n i nh ib its th ro mb in fo rma ti on

Na2EDTA binds calcium

Gray Sodium fluoride/potassium oxalate Plasma/glucose testing Inhibits glycolysis

Yellow Sterile containing sodiumpolyanetholesulfonate

S er um /m ic ro biology c ul tu re A ids in bac te ri al r eco very by inh ib it ingcomplement, phagocytes, andcertain antibiotics

Yellow Acid citrate dextrose Plasma/blood bank, HLA phenotyping,and paternity testing

WBC preservative

Tan (glass) Sodium heparin Plasma/lead testing Inhibits thrombin formation

Tan (plastic) K2EDTA Plasma/lead testing Chelates (binds) calcium

Yellow/gray and orange Thrombin Serum/chemistry Clot activator

Red/gray and gold Clot activator separation gel Serum/chemistry Silica clot activator

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EFFECT OF

INCORRECTANTICOAGULANT

++ ++

Additive Test Effect

EDTA Alkaline phosphatase InhibitsCreatine kinase InhibitsL eucine a mino pe pt idas e Inh ib it sCalcium and iron DecreasePT and PTT IncreaseSodiu m and p otassiu m IncreasePlatelet a ggregation Prevents

Oxalate Acid phosphatase InhibitsAlkaline phosphatase InhibitsAmylase InhibitsLD InhibitsCalcium DecreasesSodiu m and p otassiu m IncreaseCell morphology Distorts

Citrate ALT and AST InhibitAlkaline phosphatase InhibitsAcid phosphatase StimulatesAmylase DecreasesCalcium DecreasesSodiu m and p otassiu m IncreaseLabile coagulat ion factors P reserve

Heparin Triiodothyronine IncreasesThyroxine IncreasesPT and PTT Increase

Wrights stain Causes blue backgroundLith ium (L iHep tubes on ly) IncreasesSodium (NaHep tubes on ly) Increases

Fluorides Acid phosphatase DecreasesAlkaline phosphatase Decreases

Amylase DecreasesCreatine kinase Decreases

ALT and AST DecreaseCell morphology Distorts

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PROPER ORDER OF DRAW

l l l ll ll

Order of Draw: Evacuated Tube and Syringe

1. Blood-culture tubes (yellow)

2. Coagulation sodium citrate tube (blue stopper)

3. Serum tubes with or without clot activator or gel separator

4. Heparin tubes with or without gel (green stopper)

5. Ethylenediaminetetraacetic acid tubes (lavender stopper)

6. Glycolytic inhibitor tubes (gray stopper)

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Rationale of the

order of draw

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TABLE 2-3 ORDER OF DRAW, STOPPER COLORS, AND RATIONALE FOR COLLECTION ORDER

O RD ER OF DR AW T UB E S TO PP ER CO LO R R AT IO NA LE FO R C OL LE CT IO N O RD ER

Blood cultures (ster ile Yel low SPS Minimizes chance of microbial contaminationcollections) Sterile media bottle

C oa gu lat io n t ub es L ig ht bl ue T he fi rst ad di ti ve tu be in th e o rd er bec au se al l o th er

additives affect coagulation tests

G las s n on ad di ti ve t ub es R ed P re ve nt s c on tam in at io n b y a dd it iv es i n o th er t ub es

P la st ic c lo t a ct ivat or t ubes Red F il le d a ft er c oa gu la ti on t es ts bec ause s il ic a par ti cl esSerum separator tubes Red and gray rubber activate clotting and affect coagulation tests (carry-over

(SSTs) Gold plastic of silica into subsequent tubes can be overridden byanticoagulant in them)

Plasma separator tubes Green and gray rubber Heparin affects coagulation tests and interferes in(PSTs) Lig ht-green plastic co llection of serum specimens; causes the leastHeparin tubes Green interference in tests other than coagulation tests

EDTA tubes Lavender Responsible for more carry-over problems than any otherPink additive: elevates Na and K levels, chelates and decreases

P lasma preparation Pearl top calcium and i ron levels, e levates PT and PTT results

tubes (PPTs) Sodium fluoride and potassium oxalate affectO xal ate /f lu or id e t ub es G ray s od iu m an d p ot as siu m l ev el s, res pe cti ve ly , a ft er hem at ol-

ogy tubes because oxalate damages cell membranes and

causes abnormal RBC morphology. Oxalate interferes inenzyme reactions.

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Blood collection

procedure: open system1. Check request slip

2. Identify the patient

3. Verify diet restrictions/fasting

4. Put on gloves and assemble the equipment

5. Reassure and position the patient

6. Apply tourniquet

7. Select the venipuncture site

8. Cleanse the area

9. Inspect the needle and syringe19

Blood collection

procedure: open system

10.

Tie the tourniquet

11. Perform venipuncture

12. Remove tourniquet before pulling out the needle.

13. Apply cotton/bandage

14. Transfer blood collected to appropriate tubes (mix ifnicessary)

15. Label tubes

16. Dispose contaminated materials

17. Transport specimen immediately

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Blood collection

procedure1. Check request slip

2. Identify the patient

3. Verify diet restrictions/fasting

4. Put on gloves and assemble the equipment

5. Reassure and position the patient

6. Apply tourniquet

7. Select the venipuncture site

8. Cleanse the area

9. Inspect the needle and syringe21

Blood collection

procedure10. Tie the tourniquet

11. Perform venipuncture

12. Fill the tubes and mix if necessary

13. Release the tourniquet before withdrawing theneedle

14. Apply bandage

15. Label tubes

16. Dispose contaminated materials

17. Transport specimen immediately22

Specimen Variables

Pre-analytical

Analytical

Post-analytical

i i i l l ll i . i l ll i

ll i l i . i i i

Technologist picksup tubes

RepeatY

Patient ID

Patient confirmation

Check request &patient preparation

yes

no

Politely explain why &give correct instructions

end

Prepare materials& collect blood

Forward bloodinside the lab

Label specimen

Inside

thelab

Receipt oflab. request

Meet patient prep

i i i l l ll i .i l ll i

ll i l i . i i i

Tubes sorted byrequirements/degree

of urgency

Technologist placesspecimens in thehematology racks

Racks carried to theanalyzers and

processed

Reports pulled anddata collated

Results reviewed

A

i i i l l ll i . i l ll i

ll i l i . i i i

Tubesplacedinpending analysis

racks

Specimensreanalyzed

Originalandrepeatedresults

filedtogether

NO

YES

Encode results& sign

Release results

end

Technologistplaces specimen

in CC racks

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Pre-COLLECTION

Patient preparation

Patients request

Blood collection

Specimen Labeling

Entry to logbook

Specimen preparation

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POSTURE

! leads to efflux ortransfer of filterablesubstances from the

intravascular space tothe interstitial

! increases TP, Bilirubin,Lipids, and enzymes

STRESS

! affect secretions ofadrenal hormones

! leads tohyperventilation

! disturbance of acid-base balance affecting ABG test

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Diurnal rhythms

body fluids and analytes fluctuations during theday

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Tests Affected by Diurnal Variation, Posture, and Stress

Cortisol Peaks 46 AM; lowest 8 PM12 AM; 50% lower at8 PMthan at 8 AM; increased with stress

Adrenocorticotropichormone

Lower at night; increased with stress

Plasma renin activity Lower at night; higher standing than supine

Aldosterone Lower at night

Insulin Lower at night

Growth hormone Higher in afternoon and evening

Acid phosphatase Higher in afternoon and evening

Thyroxine Increases with exercise

P rola ct in Hi gh er wi th st re ss; hi ghe r l eve ls a t 4 a nd 8 AMand at 8 and 10 PM

Iron Peaks early to late morning; decreases up to30% during the day

Calcium 4% decrease supine

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Specimen collection

en Common Errors in Specimen Collection

1. Misidentification of patient

2. Mislabeling of specimen

3. Short draws/wrong anticoagulant/blood ratio

4. Mixing problems/clots

5. Wrong tubes/wrong anticoagulant

6. Hemolysis/lipemia

7. Hemoconcentration from prolonged tourniquet time

8. Exposure to light/extreme temperatures

9. Improperly timed specimens/delayed delivery to laboratory

10. Processing errors: Incomplete centrifugation, incorrect log-in, improper

storage

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Reasons for Specimen Rejection

Hemolysis/lipemia

Clots present in an anticoagulated specimen

Nonfasting specimen when test requires fasting

Improper blood collection tube

Short draws, wrong volume

Improper transport conditions (ice for blood gases)

Discrepancies between requisition and specimen label

Unlabeled or mislabeled specimen

Contaminated specimen/leaking container34

Specimen collection

Effect of hemolysis

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Changes in Serum Concentration (or Activities) of SelectedConstituents Due to Lysis of Erythrocytes (RBCs)

Constituent

Ratio ofconcentration (oractivity) in RBC toconcentration (or

activity) in serum

Percent change ofconcentration (oractivity) in serumafter lysis of 1%RBC, assuming a

hematocrit of 0.50Lactate dehydrogenase 16 : 1 +272.0

Aspartateaminotransferase

4 : 1 +220.0

Potassium 23 : 1 +24.4

Alanineaminotransferase

6.7 : 1 +55.0

Glucose 0.82 : 1 5.0

Inorganic phosphate 0.78 : 1 +9.1

Sodium 0.11 : 1 1.0

Calcium 0.10 : 1 +2.9

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Needle insertion

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When a vein rolls, the needle mayslip to the side of the vein withoutpenetrating it

Correct insertion technique; bloodflows freely into needle

A

B

D

G

C

E

Bevel on vein lower wall does not

allow blood to flow

Needle partially inserted andcauses blood leakage into tissue

Bevel on vein upper wall does notallow blood to flow

Needle inserted too far

Collapsed

F

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Specimen Collection and Processing