1. Introduction to Laboratory Medicine
Roger L. Bertholf, Ph.D.

2. Some SHJ Lab Statistics
Number of employees: 130
Number of tests/year: 1.5 million
Yearly budget: $16 million
Yearly revenue: $70 million
Net $25 million

3. Laboratory organization
Core Laboratory (73% of volume)
Chemistry, hematology, toxicology, immuno-chemistry, special chemistry, coagulation, urinalysis
Microbiology (16 % of volume)
Blood/urine cultures, serology
Transfusion Services (3% of volume)
Blood typing and cross-matching

4. Chemistry
Electrolytes, glu, BUN, creat, phos, TP, Bili, Mg, Ca, cholesterol, triglycerides, etc.
Blood gases: pO2, pCO2, pH, calc. Parameters
Immunochemistry: endocrine, specific protein, tumor markers
Toxicology: DAU, TDM
Urinalysis
Special Chemistry: electrophoresis, L/S ratio, FLM, osmometry

5. SHJ Chemistry Instruments
Roche/Hitachi Modular and 914
Chemistries and homogeneous immunoassays
Roche Elecsys 2010
Heterogeneous immunoassays
NOVA M (whole blood gas/electrolytes)
Abbott IMx
Yellow Iris

6. Hematology
CBC/Diff
Coagulation
Microscopy

7. SHJ Hematology Instruments
Abbott Cell Dyne 4000
CBC, Auto differential
Organon Technika MDA
Coagulation

8. Microbiology Cultures Antibiotic sensitivity Serology Blood Urine
Sputum, wound, etc.
Antibiotic sensitivity
Serology
Viral Ab, Ag testing

9. Point of Care Testing
Instruments are available that can perform certain tests at remote locations, such as at the bedside on in a clinical care unit
Blood glucose
Urinalysis
Blood gases
Electrolytes/BUN/Creatinine
Cardiac markers (Troponin I & T, CK-MB)
Coagulation (ACT)
POC tests are nearly always more expensive, than the same tests performed in the central laboratory

10. POCT at SHJ Blood glucose (Not under lab license)
Electrolytes on the GEM Premier in the OR
ACT in the OR and Cardiac Catheterization Lab
Urinalysis (not under lab license)

11. Reasons for POC testing
Tests are of urgent importance, and results will affect the immediate management of the patient
Blood gases, electrolytes
Tests are so common, simple and cheap that it is more economical to perform them at the point of care
Blood glucose, urinalysis

12. SHJ Blood Gas Lab Operated by Respiratory Therapy
Performs blood gases and whole blood electrolytes/BUN/Creatinine/Glucose
Gases fall under RT license
Chemistries fall under the lab license
Serves MICU, CCU, PICU, NICU, SICU
Performs all co-oximetry

13. Steps in obtaining a laboratory test
Written order is placed
Specimen is collected and properly labeled
Specimen and order are transported to the lab
The specimen is accessioned in the lab
The specimen is processed
The specimen is analyzed
The results are reviewed and verified by an MT
The results are released to the patient’s record

14. How long steps 4-7 take (P1 orders)

15. How long steps 4-7 take (STAT)

16. Sources of error in laboratory results
Pre-analytical
Analytical
Post-analytical

17. Pre-analytical errors
Collection
Was the right tube used?
Was venipuncture performed correctly?
Was the specimen properly stored?
Identification
Was the blood collected from the correct patient?
Was the blood correctly labeled?
Patient name, ID, date, time of collection, phlebotomist

18. Collection tubes
Red-top tubes contain no anticoagulants or preservatives
Red-top tubes are used for collecting serum
10-15 minutes is required to allow blood to clot before centrifuging
Used for blood bank specimens, some chemistries

19. Collection tubes
Gold (and “tiger”) top tubes contain a gel that forms a physical barrier between the serum and cells after centrifugation
No other additives are present
Gel barrier may affect some lab tests

20. Collection tubes Gray-top tubes contain either:
Sodium fluoride and potassium oxalate, or
Sodium iodoacetate
Both perservatives stabilize glucose in plasma
NaF/oxalate inhibits enolase
Iodoacetate inhibits glucose-3-phosphate dehydrogenase

21. Collection tubes
Green-top tubes contain either the sodium or lithium salt of heparin
The amount of Na+ or Li+ is insignificant
Heparin inhibits thrombin, so blood does not clot (plasma)
The advantage of plasma is that no time is wasted waiting for the specimen to clot

22. Collection tubes
Lavender-top tubes contain EDTA, which chelates calcium and inhibits coagulation
Used for hematology, and some chemistries

23. Collection tubes
Blue-top tubes contain sodium citrate, which chelates calcium and inhibits coagulation
The blood/anticoagulant ratio must be precisely known, since the tubes are used for coagulation studies.

24. Collection tubes
Brown and Royal Blue top tubes are specially cleaned for trace metal studies
Brown-top tubes are used for Pb analysis
Royal blue-top tubes are used for other trace element studies (acid washed)

25. Plasma/Serum differences
Plasma concentration greater than serum:
Ca (+0.9%), LD (+2.7%), TP (+4.0%)
Plasma concentration less than serum:
Alb (-1.3%), ALKP (-1.6%), HCO3- (-1.8%), CK (-2.1%), PO4= (-7.0%), K+ (-8.4%)

26. Prolonged venous stasis
Increases TP, Fe, cholesterol, AST, bilirubin
Decreases potassium

27. Supine vs. sitting or standing
The following may decrease by 5-15% in the supine patient:
Total protein
Albumin
Lipids
Iron
Calcium
Enzymes Ig
Thyroxine

28. Significantly affected by hemolysis:
Total protein, albumin, lipids, iron, calcium, enzymes, bilirubn, cholesterol, triglycerides, norepinephrine, renin, aldosterone, potassium, magnesium, phosphorous

29. Specimens requiring special handling
Should be placed immediately on ice
Lactate
Ammonia
Acid phosphatase
Plasma catecholamines

30. Exertion-related changes
Recent strenuous exercise increases:
Acid phosphatase, ALT, AST, creatinine, phosphorous, CK
Recent strenuous exercise decreases:
Iron, lipids, potassium

31. Other factors affecting lab results
Diurnal variations
Cortisol, iron, estriol, glucose, catecholamines
Age
Creatinine, BUN, ALKP, drug metabolism
Smoking
Ammonia, CO-Hb

32. Specimen identification
One of the commonest sources of erroneous lab results is misidentified specimens
CAP and other accrediting agencies require the lab to have a clear and rational policy for identifying specimens, and handling misidentified specimens
The blood bank has stricter requirements for specimen identification

33. Misidentified specimens at SHJ
29: Delay in obtaining lab results
26: Specimen collected/labeled/registered with wrong patient
46: Specimen unlabeled/mislabeled/labeled incompletely