1) Errors during specimen collection account for 70% of all laboratory errors and can compromise patient diagnosis and treatment. Proper collection, handling, and transportation of specimens is crucial for accurate laboratory results. 2) Many factors can affect specimen quality, from patient preparation and phlebotomy technique to tube type and filling. Strict adherence to collection protocols helps ensure specimens are not compromised before analysis. 3) Education and training of phlebotomists is important to prevent errors. Ongoing competency assessments and use of technology like barcode scanners also help ensure specimens are correctly collected and labeled.

1. CLINICAL CHEMISTRYCLINICAL CHEMISTRY
SPECIMENSPECIMEN
REQUIREMENTSREQUIREMENTS

2. DR . Naglaa MakramDR . Naglaa Makram
Asistant. Prof . clinical pathologyAsistant. Prof . clinical pathology

3. Role ofRole of
specimen inspecimen in
lab Resultlab Result
accuRacyaccuRacy

4. IntroductionIntroduction
 Three phases of laboratory testing:Three phases of laboratory testing:
pre-analytical, analytical and post-analyticalpre-analytical, analytical and post-analytical
 Pre-analyticalPre-analytical—specimen collection, transport—specimen collection, transport
and processingand processing

5.  Pre- analytical errors are estimated to constitutePre- analytical errors are estimated to constitute
7070% of errors% of errors
 Errors at any stage of the collection, transportErrors at any stage of the collection, transport
can potentially lead to a serious patientcan potentially lead to a serious patient
misdiagnosismisdiagnosis
 Errors during the collection process are notErrors during the collection process are not
inevitableinevitable but can bebut can be preventedprevented withwith
continuing education and effective collectioncontinuing education and effective collection
systems.systems.

6. Implications of errorsImplications of errors
 andand
compromisecompromise
the diagnosisthe diagnosis
and treatmentand treatment
of the patientof the patient
• may influence the
quality of the final
measured
results ...
• Errors made in the
period prior to the
analysis of the
sample ...

7. Preparation prior toPreparation prior to
samplingsampling
Sampling/handling
Storage/transport
Preparation prior
to analysis

8. No result is
better than bad
result

9.  Sampling TechniqueSampling Technique
 Test Collection ProceduresTest Collection Procedures
 Specimen TransportSpecimen Transport

10. Collect Sample:Collect Sample:
 Locate PatientLocate Patient
 Prep PatientPrep Patient
 Draw SampleDraw Sample
 LabelLabel
 Dispose of suppliesDispose of supplies

11.  WhenWhen identifyingidentifying the patient, have themthe patient, have them
provide theirprovide their fullfull namename,, ididentificationentification numbernumber
and/orand/or date of birthdate of birth..
 Hospital NoHospital No inpatients should be wearing aninpatients should be wearing an
ididentificationentification bandband with the abovewith the above
information, which the phlebotomist shouldinformation, which the phlebotomist should
confirm before the venipuncture.confirm before the venipuncture.
Patient identificationPatient identification

13.  It is important toIt is important to identifyidentify aa patient accuratelypatient accurately soso
that blood isthat blood is collectedcollected from thefrom the correct personcorrect person..
 Drawing blood from the wrong person, or labelingDrawing blood from the wrong person, or labeling
the correct patient’s sample with a differentthe correct patient’s sample with a different
patient’s label can certainly contribute to laboratorypatient’s label can certainly contribute to laboratory
error. (error. (Mislabeling ???Mislabeling ???))
 AllAll specimens must be labeled at the bedsidespecimens must be labeled at the bedside
Effects on the Quality of LaboratoryEffects on the Quality of Laboratory
TestingTesting

14. Factor affecting lab resultFactor affecting lab result
 Some patient variables that affect test resultsSome patient variables that affect test results
AgeAge
GenderGender
DietDiet
ExerciseExercise
PosturePosture
Haemolysis, lipemiaHaemolysis, lipemia
 IcterusIcterus
 DrugsDrugs

15.  TSH 6.5TSH 6.5
• NEONATE UP TO 8.3NEONATE UP TO 8.3
• ADULT UP TO 4.2ADULT UP TO 4.2

16. Test CollectionTest Collection
 Timing of CollectionTiming of Collection
 Therapeutic Drug MonitoringTherapeutic Drug Monitoring
 PeakPeak andand troughtrough collection timescollection times
 Basal State CollectionsBasal State Collections
 FastingFasting requirements—no food or liquid exceptrequirements—no food or liquid except
waterwater(10-12h)(10-12h)
 2h postprandial, from the2h postprandial, from the startstart of food .of food .
 Specimens affected by time of daySpecimens affected by time of day, for example,, for example,
cortisol, iron and TSH.cortisol, iron and TSH.

17. PhlebotomyPhlebotomy
 Phlebotomy is a highly complex skill requiringPhlebotomy is a highly complex skill requiring
expertexpert knowledgeknowledge, and, and criticacritical judgmentl judgment
 venipuncture is a frequent medical procedure.venipuncture is a frequent medical procedure.
 Phlebotomy errors may causePhlebotomy errors may cause harmharm to patientsto patients
or result inor result in needle stickneedle stick injury to theinjury to the
phlebotomistphlebotomist

18. Error PreventionError Prevention
 Phlebotomy EducationPhlebotomy Education
 Phlebotomists should have completed a standardPhlebotomists should have completed a standard
academic course in phlebotomy and undergoacademic course in phlebotomy and undergo
thorough on-the-job training under the supervisionthorough on-the-job training under the supervision
of a senior phlebotomistof a senior phlebotomist
 Continuing EducationContinuing Education
 Phlebotomists should participate in regularPhlebotomists should participate in regular
educational competency assessments (written andeducational competency assessments (written and
observational)observational)
 Professional LicensureProfessional Licensure
 Phlebotomy StaffingPhlebotomy Staffing
 Adequate staffing to maintain collection standardsAdequate staffing to maintain collection standards
 TechnologyTechnology
 Use of barcode scanners for patient identificationUse of barcode scanners for patient identification

19. 1-posture:1-posture:
• The patient should be comfortably seated orThe patient should be comfortably seated or
supine for 20 minutes before sampling . Notsupine for 20 minutes before sampling . Not
standingstanding
• The patient arm should be extended in a straightThe patient arm should be extended in a straight
line from the shoulder to the wrist.line from the shoulder to the wrist.
2-2- collection site.collection site.
• The median cubital vein is the preferred site.The median cubital vein is the preferred site.
• Veins on the hand or at ankle may be usedVeins on the hand or at ankle may be used..

20. Avoid the arm with:
•Extensive scarring or hematoma .,infection ,
edema ,burn .
•Containing I.V. access for I.V. infusion.
•On the side of mastectomy.

21. Phlebotomy TechniquePhlebotomy Technique
 Correct collection systemCorrect collection system
 Evacuated tube system (Vacutainer) for large veinsEvacuated tube system (Vacutainer) for large veins
in antecubital fossain antecubital fossa
 Syringe for small, fragile veins or veins outsideSyringe for small, fragile veins or veins outside
antecubital fossaantecubital fossa
 Venous accessVenous access
 Needle entry should be at 15 to 30 degreesNeedle entry should be at 15 to 30 degrees
depending on depth of veindepending on depth of vein
 Needle entry should be in same direction as vein,Needle entry should be in same direction as vein,
centered over veincentered over vein
 Anchor vein to prevent movement during needleAnchor vein to prevent movement during needle
entry and to reduce pain to patiententry and to reduce pain to patient

23. Phlebotomy Technique ErrorsPhlebotomy Technique Errors
 Tourniquet ApplicationTourniquet Application
 Tourniquet tied too close to the venipuncture siteTourniquet tied too close to the venipuncture site
can cause hematomacan cause hematoma
 Veins may not become prominent if tourniquet isVeins may not become prominent if tourniquet is
tied too high (more than 3 to 4 inches abovetied too high (more than 3 to 4 inches above
venipuncture sitevenipuncture site))
 Tourniquet left on longer than one minute can resultTourniquet left on longer than one minute can result
inin hemoconcentrationhemoconcentration , affecting some test results, affecting some test results
 Tourniquet should be released as soon as needleTourniquet should be released as soon as needle
is in the lumen of the vein and blood flowis in the lumen of the vein and blood flow
establishedestablished

24. Change the position of the needle.
Move it forward (it may not be in
the lumen)

25. or move it backward (it may have
penetrated too far).
Adjust the angle (the bevel may
be against the vein wall).

26. Phlebotomy TechniquePhlebotomy Technique
 Cleansing of venipuncture siteCleansing of venipuncture site
 Thorough cleaning with alcoholThorough cleaning with alcohol
 Allow alcohol to dry completely to avoid stingingAllow alcohol to dry completely to avoid stinging
sensation upon needle entry andsensation upon needle entry and hemolysishemolysis ofof
samplesample

27. Factors Leading to Difficult VeinFactors Leading to Difficult Vein
ConditionsConditions
 AnxietyAnxiety
 ColdCold
 Vasoconstriction of veinsVasoconstriction of veins
 Repeatedly punctured veinsRepeatedly punctured veins
 Sclerosed veinsSclerosed veins
 Rolled veinsRolled veins
 Delicate veins (children / women)Delicate veins (children / women)
 Poor hydrationPoor hydration
 Pre-shock or shockPre-shock or shock
 Brittle veinsBrittle veins
 Long term treatment with steroidsLong term treatment with steroids

28. Test CollectionTest Collection
 AdditiveAdditive : EDTA , lithium heparin , flourid: EDTA , lithium heparin , flourid
 HemolysisHemolysis
 Blood collected insufficient to amount of additive inBlood collected insufficient to amount of additive in
tubetube
 Traumatic venipunctureTraumatic venipuncture
 Blood collected from area with hematomaBlood collected from area with hematoma
 Vigorous shaking of tubes after collectionVigorous shaking of tubes after collection
 Milking the site when collecting capillary samplesMilking the site when collecting capillary samples
and blood collected using a small diameter needle.and blood collected using a small diameter needle.

29. Test CollectionTest Collection
 Capillary Collections—finger stick or heel stickCapillary Collections—finger stick or heel stick
 Appropriate siteAppropriate site
 Heel stick—sides of the bottom surface of the heelHeel stick—sides of the bottom surface of the heel
 Finger stick—third or fourth fingers, perpendicular toFinger stick—third or fourth fingers, perpendicular to
fingerprint lines on fleshy pads on finger surfacefingerprint lines on fleshy pads on finger surface
 Warming—Warming—Warm before collection to increaseWarm before collection to increase
capillary blood flow near skin surfacecapillary blood flow near skin surface
 Cleaning—cleanse site with alcohol and allow to airCleaning—cleanse site with alcohol and allow to air
drydry
 Discard first drop of blood.Discard first drop of blood.

30. 1.1. Blood Culture Bottles (Aerobic-Anaerobic)Blood Culture Bottles (Aerobic-Anaerobic)
2.2. Coagulation TubeCoagulation Tube
3.3. Serum Tube with or without clot activator, with orSerum Tube with or without clot activator, with or
without gel separatorwithout gel separator
4.4. Heparin Tube with or without gel plasma separatorHeparin Tube with or without gel plasma separator
5.5. EDTAEDTA
6.6. Glycolytic InhibitorGlycolytic Inhibitor
Recommended order of draw (NCCLS):Recommended order of draw (NCCLS):

32.  All blood collectionAll blood collection tubes need to be filled to thetubes need to be filled to the
correct volumecorrect volume..
 This will ensure theThis will ensure the proper amount of bloodproper amount of blood for thefor the
amount ofamount of additiveadditive in the tube (blood to additivein the tube (blood to additive
ratio).ratio).
 For example,For example, if a 5 mL draw heparin tubeif a 5 mL draw heparin tube is onlyis only
filled with 3 mLfilled with 3 mL of blood,of blood, the heparinthe heparin concentrationconcentration
is erroneously highis erroneously high andand maymay potentiallypotentially interfereinterfere
with some chemistry analytes,with some chemistry analytes,
Correct Specimen VolumeCorrect Specimen Volume

33.  AllAll tubes with additives need to betubes with additives need to be invertedinverted
to mix the additive evenlyto mix the additive evenly with the blood.with the blood.
 ImproperImproper mixingmixing of the tube afterof the tube after
venipuncturevenipuncture could contribute to samplecould contribute to sample
clotting.clotting.
Proper Tube MixingProper Tube Mixing

34. POINTS TO CONSIDER REGARDINGPOINTS TO CONSIDER REGARDING
COLLECTING BLOOD SPECIMEN FROM ACOLLECTING BLOOD SPECIMEN FROM A
LIMB WITH I.VLIMB WITH I.V
 Blood specimen should not be drawn from an arm withBlood specimen should not be drawn from an arm with
I.V.I.V.
 * If it’s no way except to use an arm with an IV line, do* If it’s no way except to use an arm with an IV line, do
the following:the following:
 Specimen should be collectedSpecimen should be collected belowbelow IVF infusion site,IVF infusion site,
never abovenever above, and use the following procedure:, and use the following procedure:
 Turn off the IVF for a minimum of 2 minutes prior toTurn off the IVF for a minimum of 2 minutes prior to
collection.collection.
 Apply the tourniquetApply the tourniquet distaldistal to the IVF infusion site.to the IVF infusion site.

35.  Perform the venipuncture in a different veinPerform the venipuncture in a different vein
other than the one with the IVF.other than the one with the IVF.
 Collect a 5ml tube of blood prior to testCollect a 5ml tube of blood prior to test
specimen or 10 ml prior to coagulation tests andspecimen or 10 ml prior to coagulation tests and
discard then collect the required specimen.discard then collect the required specimen.
 State on the requisition form thatState on the requisition form that “the specimen“the specimen
was collected from an arm with an IVF”. It’swas collected from an arm with an IVF”. It’s
also helpful to indicate the type of the IV fluidalso helpful to indicate the type of the IV fluid
infused.infused.
 * Drawing a specimen from a limb with I.V.* Drawing a specimen from a limb with I.V.
therapy is a cause of wrong results.therapy is a cause of wrong results.

36. CEREBROSPINAL FLUID (CSF)CEREBROSPINAL FLUID (CSF)
 Each tube should contain 4ml.Each tube should contain 4ml.
 Tubes should be in the following order, in sterile plainTubes should be in the following order, in sterile plain
tube.tube.
 Tube No: 1 for Chemistry or Serology.Tube No: 1 for Chemistry or Serology.
 Tube No: 2 for Microbiology.Tube No: 2 for Microbiology.
 Tube No: 3 for Cytological examination (Hematology).Tube No: 3 for Cytological examination (Hematology).
 up to 20 ml of fluid could be removed safely from anup to 20 ml of fluid could be removed safely from an
adult.adult.
 Rapid processing of specimen is important especiallyRapid processing of specimen is important especially
glucose measurement.glucose measurement.
 Specimen for blood glucose must accompany CSFSpecimen for blood glucose must accompany CSF
sample for glucose.sample for glucose.

37. Pleural, Pericardial and Ascitic FluidPleural, Pericardial and Ascitic Fluid
 lain tube.lain tube.
 Please forward blood sample in plain tube forPlease forward blood sample in plain tube for
chemical analysis along with the above fluids tochemical analysis along with the above fluids to
aid differentiating exudates and transudatesaid differentiating exudates and transudates

38. Glucose Tolerance TestGlucose Tolerance Test
 Instruct the client to fast for 10 to 16 hours before theInstruct the client to fast for 10 to 16 hours before the
test.test.
 Instruct the client to avoid strenuous exercise for 8 hoursInstruct the client to avoid strenuous exercise for 8 hours
before and after the test.before and after the test.
 Instruct the client that the test will take 3 to 5 hours,Instruct the client that the test will take 3 to 5 hours,
requires extraction of multiple blood samples.requires extraction of multiple blood samples.
 The patient is asked to drink 75mg glucose dissolved inThe patient is asked to drink 75mg glucose dissolved in
cold water or patient can be given standard glucosecold water or patient can be given standard glucose
solution (in children the dose of glucose is 1.75mg/kgsolution (in children the dose of glucose is 1.75mg/kg
body weight.body weight.
 Blood samples should be collected in 30 min, 60 min, 90Blood samples should be collected in 30 min, 60 min, 90
min, 120 min and 180 minutes.min, 120 min and 180 minutes.

39. URINE PRESERVATIVESURINE PRESERVATIVES
 Preservatives have different roles but are usuallyPreservatives have different roles but are usually
added to reduce bacterial action oradded to reduce bacterial action or
 chemical decomposition orchemical decomposition or
 to solubilize constituents that might otherwiseto solubilize constituents that might otherwise
precipitate out of solution.precipitate out of solution.
 Another application is to decrease atmosphericAnother application is to decrease atmospheric
oxidation of unstable compounds.oxidation of unstable compounds.
 One of the most satisfactory forms of preservationOne of the most satisfactory forms of preservation
of urine specimens is refrigeration immediatelyof urine specimens is refrigeration immediately
following collection; it is even more successfulfollowing collection; it is even more successful
when combined with chemical preservationwhen combined with chemical preservation

40. COMMONLY USED URINE PRESERVATIVESCOMMONLY USED URINE PRESERVATIVES
Analyte None Freeze
Concentrated
Hydrochloric Acid
Mild Base
(pH 8-9)
Calcium X
Magnesium &Ph X X
Osmolality
X X
Porphyrins
X
Uric acid-creat-protein
X
Vanillylmandelic A
X

41. E) Specimen transportE) Specimen transport
TemperatureTemperature
LightLight

42. Transport ErrorsTransport Errors
 TemperatureTemperature
 Specimens must be transported at the appropriateSpecimens must be transported at the appropriate
temperature for the required testtemperature for the required test
 On ice—ABGs, Ammonia,ACTHOn ice—ABGs, Ammonia,ACTH
 Avoid temperature extremes if transported viaAvoid temperature extremes if transported via
vehicle from other collection sitevehicle from other collection site
 Transport ContainerTransport Container
 Some samples need to be protected from light, forSome samples need to be protected from light, for
example, bilirubinexample, bilirubin
 Transport in leak-proof plastic bags in lockable rigidTransport in leak-proof plastic bags in lockable rigid
containers ,avoid agitation.containers ,avoid agitation.

43. Blood Specimen TransportBlood Specimen Transport
 Transport of blood specimens in the properTransport of blood specimens in the proper
manner after collection ensures the quality of themanner after collection ensures the quality of the
samplesample
 TimingTiming
 Some specimens must be transportedSome specimens must be transported immediatelyimmediately
after collection, for example Arterial Blood Gasesafter collection, for example Arterial Blood Gases..
 Specimens for serum or plasma chemistry testingSpecimens for serum or plasma chemistry testing
should be centrifuged and separated within twoshould be centrifuged and separated within two
hourshours

44.  Certain chemistryCertain chemistry analytesanalytes willwill requirerequire the tube ofthe tube of
bloodblood to beto be chilledchilled after collection in orderafter collection in order toto
maintainmaintain thethe stabilitystability of the analyte.of the analyte.
 A slurry of ice and water is recommended forA slurry of ice and water is recommended for
chillingchilling the tubes of blood.the tubes of blood.
 Examples : adrenocorticotropic hormone (Examples : adrenocorticotropic hormone (ACTHACTH),),
angiotensin converting enzyme (angiotensin converting enzyme (ACEACE), acetone,), acetone,
ammoniaammonia, catecholamines, free fatty acids, lactic, catecholamines, free fatty acids, lactic
acid, pyruvate and renin ,PTHacid, pyruvate and renin ,PTH
Special Handling of Blood SpecimensSpecial Handling of Blood Specimens

45. Blood gases analysisBlood gases analysis
“Collection of a blood specimen, as well as its handling
and transport, are key factors in the accuracy of clinical
laboratory analysis and ultimately in delivering quality
patient care”
”Arterial blood is one of the most sensitive of the
specimens sent to the clinical laboratory for analysis”
”Blood gas and pH analysis has more immediacy
on patient care than any other laboratory
determination”
”In blood gas and pH analysis an
incorrect result can often be worse for
the patient than no result at all”

46. What is so special about bloodWhat is so special about blood
gases?gases?
 NOT like other blood samplesNOT like other blood samples
 STAT parametersSTAT parameters
 Short Turn Around TimeShort Turn Around Time
 Must be analyzed within aMust be analyzed within a
short timeshort time
 ppOO22,, ppCOCO22, pH, LAC, GLU, pH, LAC, GLU
 Valuable results right nowValuable results right now
 Not in one hourNot in one hour
 Sample composition changesSample composition changes
 Patient status changesPatient status changes

47. Preparation priorPreparation prior
to samplingto sampling
Sampling/handling
• Label the sampler with patient ID
• Aspirate the sample slowly to prevent
degassing and hemolysis
• Expel any air bubbles immediately after
sampling
• Mix the sample thoroughly with heparin
after sampling

48. Storage/transport • Analyze sample immediately
• If storage is unavoidable, store the
sample at room temperature for max.
30 min.
• Samples with expected high pO2
values should be analyzed within 5
min.
Preparation prior to
sample transfer
• Before transferring the sample into the
analyzer mix thoroughly
• Visually inspect the sample for clots
and air bubbles
• Enter patient ID in analyzer logs

49.  To get a true picture of theTo get a true picture of the
patient’s respiratory condition thepatient’s respiratory condition the
patient should ideally be in a steadypatient should ideally be in a steady
state of ventilationstate of ventilation
Patients should be at rest for 5Patients should be at rest for 5
minmin
Ventilatory settings should beVentilatory settings should be
unchanged for 20 minunchanged for 20 min
 Pain and anxiety from arterialPain and anxiety from arterial
puncture may influence thepuncture may influence the
steady state of respirationsteady state of respiration
and should thus be minimizedand should thus be minimized
Stabilization of the respiratory condition

50. Storage recommendationsStorage recommendations
 Storage and transport time should be kept at aStorage and transport time should be kept at a
minimumminimum
Volatile nature of gasesVolatile nature of gases
Continued metabolism in bloodContinued metabolism in blood
 For parameter panels including GLU/LAC, be awareFor parameter panels including GLU/LAC, be aware
that 30 minutes storage might lead to biased resultsthat 30 minutes storage might lead to biased results
 It is recommended by the NCCLS to avoid cooling ofIt is recommended by the NCCLS to avoid cooling of
samples when kept in plasticsamples when kept in plastic

51. ppOO22 since oxygen will still be consumedsince oxygen will still be consumed
ppCOCO22 since carbon dioxide will still be producedsince carbon dioxide will still be produced
pHpH primarily due to the change inprimarily due to the change in ppCOCO22 andand
glycolysisglycolysis
ccCaCa2+2+
since the change in pH will influence thesince the change in pH will influence the
binding of Cabinding of Ca2+2+
to proteinto protein
ccGluGlu since glucose will be metabolizedsince glucose will be metabolized
ccLacLac due to glycolysisdue to glycolysis
Continued cellular metabolism in sampleContinued cellular metabolism in sample

52. Potential preanalytical errorsPotential preanalytical errors
• Missing or wrong patient/sample identification
• Use of the wrong type or amount of
anticoagulant
- dilution due to the use of liquid heparin
- insufficient amount of heparin
- binding of electrolytes to heparin
• Inadequate stabilization of the respiratory
condition of the patient
• Inadequate removal of flush solution in a-lines
prior to blood collection

53. Sampling /handlingSampling /handling • Mixture of venous and arterial
blood during puncturing
• Air bubbles in the sample
• Incorrect storage
• Hemolysis of blood cells
Storage and transportStorage and transport
Prep prior to transferPrep prior to transfer
• Visually inspect the sample for
clots
• Inadequate mixing of sample
before analysis
• Failure to identify the sample
upon analysis

54. Mixture of venous andMixture of venous and
arterial bloodarterial blood When puncturing an artery it isWhen puncturing an artery it is
important not accidentally to getimportant not accidentally to get
the arterial blood mixed withthe arterial blood mixed with
venous bloodvenous blood
 This may, for instance, occur, ifThis may, for instance, occur, if
you hit a vein before locating theyou hit a vein before locating the
arteryartery
 Even an admixture of a smallEven an admixture of a small
amount of venous blood mayamount of venous blood may
significantly bias the resultssignificantly bias the results
 This is especially true ofThis is especially true of ppOO22 andand
ssOO22, but other parameters may, but other parameters may
also be affectedalso be affected
Vein
Artery
40 mmHg / 5.3 kPa
100 mmHg / 13.3 kPa

55. Mixture of venous andMixture of venous and
arterial bloodarterial blood
 In arteries the bloodIn arteries the blood
pressure is high enoughpressure is high enough
to fill a self-fillingto fill a self-filling
syringesyringe
 If a self-filling syringeIf a self-filling syringe
does not fill it may bedoes not fill it may be
because a vein has beenbecause a vein has been
hithit
 In that case a newIn that case a new
sample should be takensample should be taken
Vein:
Pressure rarely
> 10 mmHg
Artery:
Systolic blood
pressure normally
> 100 mmHg

56. Inadequate removal of flushInadequate removal of flush
solutionsolution
 Flush solutions used in a-Flush solutions used in a-
lines must be removedlines must be removed
completely from the systemcompletely from the system
to avoid a dilution of theto avoid a dilution of the
blood sampleblood sample
 It is recommended toIt is recommended to
withdraw a volume equal towithdraw a volume equal to
three to sixthree to six times the “deadtimes the “dead
space” of the catheter systemspace” of the catheter system
(NCCLS)(NCCLS)

57. Inadequate removal of flushInadequate removal of flush
solutionssolutions
Sample B and A are both a-line samples taken from the same patientSample B and A are both a-line samples taken from the same patient
immediately after each otherimmediately after each other
Before taking sample BBefore taking sample B onlyonly 1 mL of saline solution was removed - the1 mL of saline solution was removed - the
tubing, however, looked redtubing, however, looked red
Before taking sample A saline solution was removed as recommendedBefore taking sample A saline solution was removed as recommended
Sample A
ctHb 6.2 mmol/L
cGlu 9.6 mmol/L
cK+
3.8 mmol/L
cNa+
130 mmol/L
cCa2+
1.00 mmol/L
cCl-
101 mmol/L
pH 7.271
pCO2 50.5 mmHg / 6.7 kPa
pO2 116.7 mmHg / 15.56 kPa
Sample B
ctHb 4.6 mmol/L
cGlu 6.9 mmol/L
cK+
2.5 mmol/L
cNa+
137 mmol/L
cCa2+
0.61 mmol/L
cCl-
113 mmol/L
pH 7.275
pCO2 35.9 mmHg / 4.8 kPa
pO2 129.3 mmHg / 17.2 kPa

58. Air bubblesAir bubbles
 Any air bubbles in the sample must beAny air bubbles in the sample must be
expelled as soon as possible after theexpelled as soon as possible after the
sample has been drawnsample has been drawn
beforebefore mixing the sample with heparinmixing the sample with heparin
beforebefore any cooling of the sampleany cooling of the sample
 Even small air bubbles may seriously affectEven small air bubbles may seriously affect
thethe ppOO22 value of the sample, normallyvalue of the sample, normally
resulting in increased valuesresulting in increased values
 An air bubble whose relative volume is 0.5An air bubble whose relative volume is 0.5
to 1.0 % of the blood in the syringe is ato 1.0 % of the blood in the syringe is a
potential source of a significant errorpotential source of a significant error

59. Effect of air bubbles - an exampleEffect of air bubbles - an example
Sample A and B were taken from the same patientSample A and B were taken from the same patient
immediately after each otherimmediately after each other
Sample A without air bubbles was analyzedSample A without air bubbles was analyzed
immediately after collectionimmediately after collection
100 µL air was added to sample B (1 mL). It was100 µL air was added to sample B (1 mL). It was
stored cold (0-4 °C) for 30 minutes and mixed for 3stored cold (0-4 °C) for 30 minutes and mixed for 3
minutes before sample analysisminutes before sample analysis
Sample A
pO2 288.6 mmHg / 38.5
kPa
(FIO2 1.000)
Sample B
pO2 253.3 mmHg / 33.8
kPa
(FIO2 1.000)

60. Insufficient mixing with heparinInsufficient mixing with heparin
 Insufficient mixing canInsufficient mixing can
cause coagulation of thecause coagulation of the
samplesample
 It is recommended to mixIt is recommended to mix
the blood samplethe blood sample
thoroughly with heparinthoroughly with heparin
 Invert the syringe 10 timesInvert the syringe 10 times
and roll it between yourand roll it between your
palmspalms

61. Inadequate mixing - anInadequate mixing - an
exampleexample
Sample A and B were taken from the same patientSample A and B were taken from the same patient
immediately after each other and stored cold for 10immediately after each other and stored cold for 10
minutesminutes
Sample A was mixed in a rotator (14 revolutions/min) forSample A was mixed in a rotator (14 revolutions/min) for
3 minutes3 minutes
Sample B was mixed in a rotator (14 revolutions/min) forSample B was mixed in a rotator (14 revolutions/min) for
1 minute1 minute
Sample B
ctHb 4.5 mmol/L
Sample A
ctHb 6.2 mmol/L

62. Hemolysis of blood cellsHemolysis of blood cells
 The blood cells are relatively fragile,The blood cells are relatively fragile,
and therefore hemolysis may easilyand therefore hemolysis may easily
occur during blood samplingoccur during blood sampling
 Hemolysis may, for instance, occurHemolysis may, for instance, occur
due todue to
 high filling pressure throughhigh filling pressure through
a narrow entrance (e.g. duringa narrow entrance (e.g. during
too vigorous sample aspiration,too vigorous sample aspiration,
sample transfer to the analyzer,sample transfer to the analyzer,
vigorous rubbing or squeezingvigorous rubbing or squeezing
of the skin during capillaryof the skin during capillary
samplingsampling
 too vigorous mixing of thetoo vigorous mixing of the
samplesample
 cooling down the samplecooling down the sample

63. ““The weak link”The weak link”
 Blood gas analyzers ofBlood gas analyzers of
today are highly accuratetoday are highly accurate
 Make sure that sampleMake sure that sample
represents patient statusrepresents patient status
 The preanalytical phase isThe preanalytical phase is
thethe weak linkweak link in thein the
Patient Focus CirclePatient Focus Circle
 Many potential errorsMany potential errors
 Can be overcome byCan be overcome by
TrainingTraining
User guidelinesUser guidelines
Sampling productsSampling products

64. Specimen Quality Markers forSpecimen Quality Markers for
RejectionRejection
 HemolyzedHemolyzed
 Underfilled, overfilledUnderfilled, overfilled
 Insufficient quantityInsufficient quantity
 Incorrect labelingIncorrect labeling
 Unlabeled specimenUnlabeled specimen
 Incorrect patientIncorrect patient
 Incorrect specimenIncorrect specimen
 ContaminatedContaminated
 Too old to processToo old to process
 Broken and leakingBroken and leaking

65. Finally…Finally…
 TheThe human rolehuman role in sample collectionin sample collection makesmakes
complete eliminationcomplete elimination of errorsof errors associatedassociated
with laboratory testingwith laboratory testing unrealisticunrealistic
 However,However, good practicesgood practices andand compliancecompliance
with the newwith the new strategiesstrategies forfor errorerror preventionprevention
can leadcan lead to ato a substantialsubstantial reductionreduction inin pre-pre-
analyticalanalytical errorserrors..

66. Thank
u