lecture 1 clinical biochem intro

Question 1

What is clinical biochemistry?

Answer 1

Clinical biochemistry is the biochemical analysis of body fluids (examples: blood, urine,
cerebrospinal fluid), to help in the screening, diagnosis, monitoring, prognosis of diseases

Question 2

Screening

Answer 2

Detection of a subclinical disease

Question 3

Monitoring

Answer 3

Evaluate the progression of a disease
and/or response to treatment

Question 4

Diagnosis

Answer 4

Confirmation or rejection of clinical
diagnosis

Question 5

Prognosis

Answer 5

Information regarding the potential
outcome of the disease

Question 6

PLASMA

Answer 6

aqueous phase of blood, which is preserved in a collection tube by the
presence of an anticoagulant. It still contains coagulation factors

Question 7

SERUM

Answer 7

aqueous phase of blood that has been allowed to clot

Question 8

What is point-of-care testing?

Answer 8

Point-of-care testing refers to all those analyses which are carried out outside the lab

Question 9

What could be potential sources of error?

Answer 9

Preanalytical
* Analytical
* Postanalytical

Question 10

Reference interval

Answer 10

the upper and lower limit that tells us the more outside it is from the RI the more likely the pathological process being present

Question 11

Clinical decision value

Answer 11

If we have to make an important decision in the management of a patient, and we
have to base it on a single result, then we need to have a “cut off” value also known
as clinical decision level (CDL) 1 limit

Question 12

SENSITIVITY

Answer 12

A tests ability to identify patients with the disease; Sensitivity tells us the percentage of individuals with
the disease who also have a positive test result
Sensitivity= 𝑇𝑃/ 𝑖𝑛𝑑𝑖𝑣𝑖𝑑𝑢𝑎𝑙𝑠 𝑤𝑖𝑡ℎ 𝑡ℎ𝑒 𝑑𝑖𝑠𝑒𝑎𝑠𝑒 (𝑇𝑃+𝐹𝑁) × 100
Negative result→ rules out a diagnosis when the test is negative (someone tests negative
therefore it does not have the disease, i.e. low D-Dimer for blood clots)
Ability of the test to detect the disease

Question 13

SPECIFICITY

Answer 13

Ability to identify patients without the disease
Specificity= 𝑇𝑁/ 𝑖𝑛𝑑𝑖𝑣𝑖𝑑𝑢𝑎𝑙𝑠 𝑓𝑟𝑒𝑒 𝑜𝑓 𝑑𝑖𝑠𝑒𝑎𝑠𝑒 (𝑇𝑁+𝐹𝑃) × 100
Specificity measures the percentage of people who are
known to be free from the disease who also test negative
Positive result→ rules in a diagnosis when the test is positive (i.e. glycated haemoglobin over 6.5 rules in diagnosis of DM)
Ability of the test to detect the absence of disease