1. Procedure of Laboratory Test and Factors Affecting Reliability of Test Result
Usi Sukorini
Departement of Clinical Pathology
Faculty of Medicine UGM
2012

2. input
process
output

3. Effects of Variables on the Quality of Laboratory Testing
Para-analytical variables (pre & post analytical variables)
Analytical variables
Pre
Analytic
Post
Test requests/ordering
Patient identification
Specimen acquisition
Specimen transport
Specimen processing
Preparation of worklists and logs
Maintenance records
Result reporting
Result interpretation
Result distribution
Competency
Controls
Methodology
Procedures
Monitoring of equipment
Monitoring of materials
Test validation

4. Process of laboratory test request
Order test
Collect sample
Transport sample to lab
Receive sample in lab
Prepare samples for testing
Transport sample to lab section
Results
Verifications
Send to clinicians

5. PREANALYTICAL PHASE

6. Expanded View of the Preanalytical Phase

7. Preanalytical phase
The processes prior to the actual analysis of the sample
Include steps needed to obtain the primary sample (e.g. blood) and to obtain the analytical specimen (e.g. plasma, serum, cells)
KNOWLEDGE
Preparation
Primary sample
Analytical specimen

8. Impact of Preanalytic Phase on Laboratory Test Outcomes
Preanalytic Steps are Labor Intensive
Steps in specimen collection are many and varied
Potential for error expands as the number of steps increase
Studies state that “32 to 75%” of inaccurate test results originate from the preanalytic phase

9. Ordering tests Order Test: Appropriate indication
Complete & correct order
Deploy staff for collection
Note urgency level
Collect supplies

10. Ordering test Indications: Indications: Screening Diagnosis
Confirmation
Therapy
Monitoring
Indications:
Sex
Age
Time of collection
Type of specimen
Urgency

11. Methods of test
Performance of test
Analytic
Diagnostic

12. Patient Preparation Fasting: Postprandial
Glucose, cholesterol: hours prior venipuncture
Postprandial
At specific time in a hormonal cycle:
Cortisol and adrenocorticotropin, have diurnal variations, where the analyte is at its highest level in the morning, and the levels gradually decrease during the course of the day
Before or After Medication Dosage
Upon Rising or after being awake for a specific period of time

13. Patient identification
Full name, address, identification number and/or date of birth
Sex
Other information in request form:
Doctor’s name & contact number
Clinical manifestation
Treatment
Time of blood collecting

14. Specimen collection
Prolonged tourniquet time can lead to an increase in various chemistry analytes, including serum protein, potassium and lactic acid due to hemoconcentration of blood at the puncture site
Prolonged tourniquet application with leak of interstitial fluid into tissue
Correct phlebotomy technique
Complete fill of tubes

15. Specimen collection
Incomplete alcohol drying following site preparation
Shear stress and subsequent rupture of red cells when collected with small bore needle
Tissue trauma during collection
Slow blood flow
Occlusion of needle lumen by vein wall

16. Specimen collection Blood Collection from Indwelling Lines
Collection by Alternate Healthcare Providers
Education is Key for Healthcare Team
Specimen Quality Issues
Hemolysis
Fluid Contamination
Dilution of Samples

17. Collecting the right specimen is of critical importance, for example:
if a diagnosis of meningitis is expected, obtaining a throat swab or a sputum sample (instead of CSF) would not be the best sample for this purpose
Coagulation test: citrated plasma
IgG anti dengue: should be collected > 5 days of fever

18. Labelling Label All Samples at the Bedside
Handwritten Labels Must be Legible
All Labels Must Contain Required
Information
Attached Labels Should Follow Guidelines for Optimum Usefulness

19. Prolonged transportation and storage
Prolonged and improper storage prior to processing of the specimen can affect the results especially since many organisms do not survive for long unless they are subcultured or kept in an environment which is rapidly changing, or vice versa
Over 0r understimation of test result
Platelet count
PT, APTT

20. Age-dependent variations
Age dependent changes of concentration or activities occur in a number of haematological and chemical analytes
Normal bacteriological flora also change with age. Hence laboratory results should be interpreted keeping in view the age of the patient

21. Variable Analyte Levels
Potassium, LDH, Mg, iron
Increased by Hemolysis
Glucose
When Cells and Serum are Not Promptly Separated

22. Effects of Improper Inversion
Clotted Samples
Improper Mixing of Anticoagulant with Collected Blood
Clotting Process Utilizes Clotting Factors
Clotted Samples Can Not Be Analyzed in Instrumentation
Require Re-Collection

23. Avoid The “Excessives”
Do NOT SHAKE
Causes Hemolysis
Avoid Excessive Heat or Cold
Deterioration of Analytes
Never Expose Whole Blood to Dry Ice
Freezing Causes Hemolysis

24. Transportation
Transport All Samples to the Laboratory as Efficiently as Possible
Transport To Lab:
Prioritize sample for transport
Send sample to lab
Pneumatic tube
Robot
Hand carry
Courier

25. Causes of hemolysis
The presence of hemolysis in the serum or plasma of a sample appears as a pink or red color to the liquid after centrifugation (or separation from blood cells)

26. Vigorous shaking of collection tubes
Frothing (buih/gelembung)of blood resulting from a loose connection of the blood collection assemblies when performing line draws
Freezing of red blood cells during storage or transportation
Exposure of cells to excessive heat during storage or transportation
Prolonged contact of serum or plasma with cells

27. Impact of Preanalytical Errors
Unusable Samples due to Quality Issues
Specimen Rejection
Specimen Recollection
Compromise of Quality Analysis
Delay or Inaccuracy in Diagnosis and Treatment
Possible Compromise of Patient Safety

28. Suggested indicators for the preanalytical phase
Standard operating procedures for specimen acceptance /rejection to be followed by all staff
Identification and monitoring of reasons for specimen rejection
Effect of improvement initiative in decreasing the rate of specimen rejection
Comparison between clinical laboratories (bench marking) of frequency and reasons for specimen rejection

29. Suggested indicators for the preanalytical phase
Potential performance measures for pre-analytical phase
Indicators of patient identification
- Wrong patient ID on the sample
- Missing patient ID on the sample
- Illegible patient ID on the sample (tidak dapat dibaca)
- Request unintelligible
Indicators of Sample collection
- Wrong collection time
- Inadequate/ inappropriate container
- Inadequate volume, Inappropriate volume to anticoagulant ratio
- Contaminated from IV line

30. Suggested indicators for the preanalytical phase
Indicators for sample transport
- Storage condition (temperature, high exposure)
- Sample deliver to the lab outside specified time
- Sample lost or not received in the laboratory
General indicators
- Physician complains
- Sample recollection
- Sample retesting
- Correction of ordered test
- Results delivery to the physician outside specified time

31. ..
The pre-analytical stage is the most important and can be critical to patient wellbeing
The analytical stage and post analytical stages depend primarily on the Quality and Integrity of the specimen submitted to the laboratory (Pre-Analytical)
Laboratory staff involved in specimen collection have a direct impact on the outcome of patients lab results

32. ANALYTICAL PHASE

33. Analytical phase Competency Controls Methodology Procedures
Monitoring of equipment
Monitoring of materials
Test validation

34. POSTANALYTICAL PHASE

35. Postanalytical phase Result reporting Result interpretation
Result distribution

39. QUALITY CONTROL (QC)
EXTERNAL
INTERNAL

41. Non-analytical Quality Control (Para-analytical Factors)
Patient preparation
Proper sample selection
Proper collection and transportation
Details of the patient and specimen identification
Proper recording of results and their interpretation
Knowledge of normal range of results and abnormalities

42. Selection of appropriate samples
An appropriate sample should be collected in an appropriate way, e.g.:
for diagnosing an acute intestinal amoebiasis, it is essential to examine the stool sample within minutes since trophozoites survive for that much time only.
Similarly examining stool samples for the eggs of Enterobius vermicularis is not as effective as a perianal swab.
Microfilaria showing nocturnal periodicity should be sampled at night only.

43. Analytical Internal Quality Control
Equipment reliability
Reagent stability, integrity and efficiency
Adequate calibration
Procedure reliability in terms of
Precision
Accuracy
Analytical specificity

44. Internal QC

45. Postanalytical quality control
Any possible remarks on the results obtained should also be entered, as well as the normal range of the results.
The significance of the results obtained should be highlighted wherever required
There should be frequent dialogue between the laboratory personnel and the physicians for appropriate use of the facilities and the right interpretation of results obtained in the laboratory
Plausibility (Hal yang masuk akal)

46. THANK YOU