1. Quality Assessment
The goal of laboratory analysis is to provide the accurate, reliable and timeliness result
Quality assurance
The overall program that ensures that the final results reported by the laboratory are correct.
QA involves in every step in the analysis process from the initial ordering of a test and the collection of the patient sample (pre analytic), analysis of the sample (analytic), and finally the distribution of result to the proper destination ( post analytic).
Quality control
A statistical process used to monitor and evaluate analytical process that produces patient results

3. How can Analytical Quality be Controlled?
1. Internal Quality Control (IQC).
daily monitoring of quality control sera
2. External Quality Assessment (EQA).
comparing of performance to other laboratories.

4. The reproducibility of your results
Quality Control used to monitor the accuracy and precision of the assay
Accuracy
The closeness of the estimated value to the true mean
Precision
The reproducibility of your results

5. Specificity Sensitivity
the ability of a diagnostic test to detect very small amounts of the analyte
The other is the ability of a test to detect truly infected individuals.
Ability to exclude false negatives
Specificity
It is the ability of a method to identify all samples which do not contain the substance being detected (identify non-infected individuals correctly).
Ability to exclude false positive

6. Linearity A quantitative analytical method is said to be linear when:
the measured value from a series of sample solutions is linearly proportional to the actual concentration or content of the analyte (true value) in the sample solutions

7. Standard deviation: the dispersion of a set of data from its mean.
X: is the mean
Xi: is an individual measurement
∑: is the operation of summation
Mean: the average values (the central point).

8. The coefficient of variation (CV)
Is the SD expressed as a percentage of the mean (average) and is more reliable means for comparing the precision at different concentration level of units.
The precision of method varies inversely with the CV; the lower the CV the greater the Precision.
Range of CV < 5-10% to consider the method is precise.

9. Levey Jennings Chart (L-J chart)
A Levey Jennings Chart, is plotted with lines representing the mean and the SDs above and below, against a suitable time interval. Most laboratories will run a series of quality control sera, covering the full clinical range(Put up the IQC specimen for at least 20 or more assay runs) and not rely on a single control with only normal values. A chart will be established for each analyte and each level of control run. The values obtained are plotted on the chart allowing a rapid visual assessment of performance to be made.

10. L-J chart
When the results are plotted, an assessment can be made about the quality of the run.
The technologist/technician performing the test should look for systematic error and random error

11. Westgard Rules There are six basic rules in the Westgard scheme.
These rules are used individually or in combination to evaluate the quality of analytical runs.
Most of the quality control rules can be expressed as NL where N represents the number of control observations to be evaluated and L represents the statistical limit for evaluating the control observations.
Thus 13s represents a control rule which is manifested when one control observation exceeds the ±3s control limits

12. Rule 13s One QC result outside ±3s
This rule identifies unacceptable random error or possibly the beginning of a large systematic error.

13. Rule 12s
This is a warning rule that is violated when a single control observation is outside the ±2s limits.
This rule warns that random error or systematic error may be present in the test system.

14. Rule 22s This rule identifies systematic error only.
The criteria for this rule are:
• Two consecutive QC results Greater than 2s on the same side of the mean
Or Both controls in the same run exceed ±2SD
Patient results cannot be reported.
Requires corrective action

16. Rule R4s This rule identifies random error only
One control exceeds the mean by –2SD, and the other control exceeds the mean by +2SD
The difference between the two results will therefore exceed 4 SD.
For example, assume both Level I and Level II have been assayed within the current run. Level I is +2.8s above the mean and Level II is -1.3s below the mean. The total difference between the two control levels is greater than 4s (e.g. [+2.8s – (-1.3s)] = 4.1s).

17. Rule 41s The criteria which must be met to manifest this rule are:
Four consecutive QC results for one level of control are outside ±1SD on the same side of the mean, or
both levels of control have 2 consecutive results that are outside ±1SD.
This allows the detection of systemic error

18. These rules are violated when there are:
Ten consecutive QC results for one level of control are on one side of the mean, or
both levels of control have five consecutive results that are on the same side of the mean (no requirement for SD size).
This allows the detection of systemic error.

19. Normal curve

20. Systematic Errors Random Errors
Errors within the test system of methodology
Affect the accuracy of result
Include:incorrect instrument calibration
Reagent that lost their activity
Ex: Shift and Trend
Occur without prediction or regularity
Affect measurement of precision and causes data to be scattered more.
Occure as the result of carelessness and when taking short cuts in procedures
Unprecise pipetting

21. Random Erorrs

22. Systematic Errors

23. Shift: Is defined as a drift of values from one level of the control chart to another, which may be sudden or gradual and may be due to failure to recalibrate when changing lot numbers of reagent during an analytical process.

24. Shift

25. Trend: Is the continuous movements in one direction over six or more consecutive values. Trends are difficult to detect without continual charting, and may start on one side of the mean and move across it or it can occur entirely on one side of the mean this problem is usually due to deterioration of reagents or light source of the instrumentations.

26. Trend

27. Differentiate between control, standard and calibrators:
A solution that contain the same constituent as those being analyzed in the patient sample
Most are commercially produced from pooled sera
Samples of known concentration that are used to monitor the accuracy and precision of an analyzer and assay
Range
Calibrators and standards
Are samples of known concentration used to adjust analyzer or instrumentation parameters.
It is used to calculate the concentration of an analyte/s in the sample.
Value

28. Concept of clinical chemistry
Analyte: The constituent or characteristic of the sample to be measured.
Assay: to analyze a sample of a specimen to determine the amount, activity, or potency of a specific analyte or substance.
Run: A series of measurements
Range: The difference between the largest and smallest observed value of a quantitative characteristic or statistical limits.
Lyophilization: Freeze- dried.
Concentration: A measure of the amount of dissolved substance per unit of volume.
Out of control: indicates that the analysis of patient samples is unreliable.

29. Analytical methods used in clinical chemistry
Spectrophotometry
Electrochemistry
photometry
Other
Chromatography
Electrophoresis