Accurate results require a comprehensive quality control program. Instrumentation, reagents and people can all make errors. A good quality assurance program, as is implemented at AVL, is designed to detect and correct errors as soon as possible.
AVL is a member of the Veterinary Laboratory Association Quality Assurance Program.
The Veterinary Laboratory Association (VLA) Quality Assurance Program is an external proficiency program specifically designed for veterinary laboratories. Each quarter AVL receives sample specimens for our laboratory to analyze and return to the VLA where the data is statistically analyzed and a customized report is returned to AVL using both graphical and numerical data. The VLA quality assurance program is a valuable supplement to our own internal quality assurance program.
Quality Assurance at AVL
Chemistry: Bi level controls are assayed daily.
Hematology: Whole blood controls and calibrators are used to verify the accuracy of our automated hematology analyzers.
Endocrinology: Controls for T4, Cortisol, FT4, and TSH are assayed daily.
Canine T4: Canine serum based bi-level control
Cortisol: Tri level immulite control and canine bi-level control
Progesterone: Tri-level control and canine bi-level control
T4: Tri level immulite control
FT4: Tri level immulite control
Canine TSH- Canine Bi-level control
The use of canine serum based bi-level controls in addition to the tri level controls increases the accuracy of our endocrinology results at AVL.
In addition to the above procedures and control methods AVL uses the following:
1) Repeat analysis of randomly-selected patient samples from the previous day, particularly hematology. Repeat analysis should show little variation from the previous day’s results. Significant variation may be indicative of “drift” and the need for calibration or other procedures to insure accuracy and reproducibility of results.
2) Repeat analysis of abnormal tests: AVL repeats testing of samples with abnormal results. Examples of some tests repeated include(for all species):
Ca <8.0 >12.0
Na <140 >160
K <3.5 >6.0
WBC < 5.0
T4 <0.9 >4.0
Note: As a quality control check, AVL refers blood smears for pathologist review at no charge when significant abnormalities are detected.
AVL has become known for providing accurate heartworm antigen results. At AVL we use the ELISA well method for heartworm antigen. All positive heartworm results must be verified by repeat analysis and must also be positive by a different Hwag methodology before being reported as positive. If EDTA blood is submitted, the presence of microfilaria is evaluated microscopically.
At AVL we take our responsibility to provide accurate, quality-controlled test results very seriously.
Quality Assurance Policies and Procedures at AVL
A. Sample Handling Procedures
Specimens are received into our laboratory and are checked to ensure:
- Specimen numbers match test requisitions.
- Specimens were submitted in correct tube/container.
- Serum samples are checked for: icterus, lipemia, and hemolysis.
B. Unique ID Numbers
- Specimens are assigned unique ID numbers.
- The ID number identifies the sample along with requested tests and is entered into the L.I.S.
- ID numbers are used only once.
C. Laboratory Information System (L.I.S.)
- Directly links laboratory instrumentation to order and record test results.
- Provide online viewing of test results from anywhere.
D. Specimen Storage
Our policy is to keep all hematology, chemistry and coagulation tubes for one week.
E. Quality Assurance
1. Laboratory Instrumentation
- AVL uses reagents and consumables that are recommended for each laboratory instrument by the manufacturer.
- AVL has service contracts for all laboratory instruments. Service is performed by authorized service representatives. Preventative maintenance procedures are performed daily, monthly, and bi-annually per the manufacturer.
- No reagents, consumables or controls are used past expiration date.
2. Hematology analyzers are calibrated using whole blood
- Calibration and controls are ran when reagent is replaced or when a new lot number is started.
- Daily use of normal and abnormal controls verifies proper system performance.
- AVL follows proper procedures when a control is out of range:
1) Recalibration and rerun of control.
2) Control must be in acceptable range prior to any testing.
3) In the event that recalibration and the rerun of control do not fall into acceptable ranges:
- Prepare fresh control.
- Prepare fresh calibrator.
- Prepare and place fresh reagent.
*If none of the above work, then manufacturer customer service is notified.
– AVL maintains quality control logs for each instrument.
- Prior to any testing, each morning quality controls are performed on each instrument and recorded in the quality control log for that instrument.
F. Validation of Testing
- AVL’s hematology analyzer has been validated for use on over 40 different animal species, including laboratory animals and fluids.
- Standard chemistry and enzyme assays have been validated for animal use.
- Special chemistry assays are validated for use prior to any testing.
G. Laboratory Personnel
- Laboratory personnel have been trained to perform proper quality control procedures.
- Laboratory personnel are only allowed to operate instruments that they have been properly trained and tested on.
- Testing is assigned to personnel based upon training, education, and complexity of testing.
- Testing is divided into three categories:
1) Entering specimens into the L.I.S.
2) Routine testing, automated assays, standard chemistry, hematology, and coagulation.
3) Advanced/Complex: Special procedures, special hematology, special chemistry.
- Medical Technologist supervises all areas of testing.
H. Instrumentation Used
Cell Dyn 3700
1) Hematology: Our research hematology analyzer is used by veterinary laboratories throughout the United States.
Hematology analyzers count and size cells for over 30 different species.
- Reticulocyte counts at no additional charge on anemic dogs and cats.
- Same day reporting and STAT availability for coagulation assays.
- Complete Blood Counts available for birds, reptiles, large animal and small animals.
2) Blood Smears: All CBCs include:
- Blood smear review/differential.
- Reflex blood parasite screen on anemic animals.
- Manual review of abnormalities that would be missed by automated methods: inclusions, toxic neutrophils, abnormal red blood cell morphology, atypical cells, platelet estimates to verify automated platelet count.
- Pathologist review at no charge on abnormal blood smears.
Immulite 1000 (Siemens)
3) Endocrinology: Immulite chemiluminescence system provides same day results for T4, FT4, TSH, cortisol and progesterone. The immulite will be found at most veterinary teaching hospitals and has largely replaced the RIA method for measuring T4.
4) Our chemistry analyzer provides accurate individual chemistries and full chemistry panels. AVL also provides same day testing for special chemistry procedures including: Bile acids, Fructosamine, CALP, and Phenobarbital levels.
Clinitek Status (Siemens)
5) Urinalysis: Urine strip reader provides accurate consistent results combined with our urine sediment examinations by phase contrast microscopy.