understanding blood science results

Question 1

what are the purposes of lab test requests? 6

Answer 1

• screening for disease
• risk stratification
• diagnosis of disease
• prognosis
• monitoring progression/ remission of disease
• monitoring therapeutic drugs and side effects of treatment

Question 2

what are the four main divisions pathology?

Answer 2

• histology and cytology (tissue diagnosis, malignancy, infection, autoimmune)
• bacteriology and virology (causes of infection, antibiotic use, public health)
• haematology (diseases of the blood, transfusion, coagulation)
• biochemistry and immunology (measurement of analytes in the blood)

Question 3

what types of samples do we analyse in clinical chemistry? 9

Answer 3

• serum
• whole blood
• urine
• faeces
• sweat
• CSF
• renal stones
• post-mortem samples
• miscellaneous fluid

Question 4

what do we need to measure in clinical chemistry 11

Answer 4

• ions
• metabolites
• waste/breakdown products
• markers of cell damage
• enzymes
• plasma proteins
• antibodies
• hormones
• drugs
• vitamins
• metals

Question 5

how are clinical chemistry tests divided into groups? 5

Answer 5

• renal function (sodium, potassium, urea, creatine)
• liver function (total protein albumin, bilirubin, alkaline phosphatase, alanine, transaminase)
• bone profile ( total protein, albumin, calcium, phosphate)
• thyroid function (TSH)
• lipid profile (total cholesterol, HDL cholesterol, triglycerides)

Question 6

what is a reference range? 10

Answer 6

• a guide to help interpret results
• open to misuse
• mean +/- 2sd
• 95% of population are within
• 2.5% are above and 2.5% are below
• results outside don’t necessarily imply disease, more extreme= more likely
• results inside do not necessarily exclude disease
• patterns of results are important
• for some things, different groups will have different reference ranges
• vary between labs