Biochemistry tests Flashcards
Define Heart failure
The inability of the heart to generate sufficient blood flow
What are the signs of HF?
Lung crackles
Oedema
Raised jugular venous pressure
What are the symptoms of HF?
Shortness of breath
Tiredness/weakness
What are the symptoms of acute coronary syndrome?
Asymptomatic disease
Stable angina
Unstable angina
Myocardial infarction
What can lead to chronic heart failure?
Hypertension COPD Valvular Disease Cardiomyopathy Infection Cardiac stress
Why is the 2D doppler echocardiography good for HF diagnosis?
Required for definitive diagnosis
Can determine type of HF
Why is BNP good for HF diagnosis?
High NPV
Used to triage patients
Cannot diagnose HF
Cannot distinguish between different types of HF
What are natriuretic peptides?
Cardiac hormones with diuretic, natriuretic and vasorelaxant properties which is secreted by the heart in response to ventricular expansion or pressure overload
What does Pro-BNP release when cleaved?
The active 32 AA BNP
An N-terminal section of 76 amino acids called NT-ProBNP
What are BNP and NT-ProBNP effective markers of?
Ventricular distension and overload
Why is BNP release and what is it’s function?
Released as a physiological response to volume expansion and pressure overload
It’s function is to reduce blood volume and peripheral resistance
It’s synthesis in bursts is directly proportional to ventricular expansion and pressure overload
What do the levels of BNP mean for diagnosis?
400ng/L = Rule in, echo and specialist review within 2 weeks
What must be considered before implementing an assay?
Analytical considerations Costs Testing protocols Interpretation Regular audit of process
What are the key benefits of BNP?
Quicker and more accurate diagnosis More timely and appropriate treatment Less time in hospital Greater convenience Fewer echo referrals Fewer outpatient consultant appointments Fewer hospital admission Shorter hospital stays
What are the limitations of BNP testing?
Cannot define the type of HF
Levels can be reduced by obesity, ACE inhibitors, beta-blockers, ARBs and aldosterone antagonists
High levels can have causes other than HF
Define infertility
Failure to conceive after regular unprotected sexual intercourse for 2 years in the absence of known reproductive pathology
What are the basic tests carried out on female patients experiencing infertility?
Mid luteal progesterone Day 3 FSH, LH, Estradiol Chlamydia screen Pelvic ultrasound scan Rubella Antibody titre Cervical smear
What is anti-mullerian hormone and what is it used for?
Produced by antral follices
Measures antral follicle pool
Used and measurement of ovarian reserve or ovarian response test prior to assisted conception treatment
What are the four levels of AMH?
Very low/undetectable - <2pmol/L
Low - 2-14pmol/L
Satisfactory - 14-28pmol/L
Optimal fertility - 29-49pmolL
What does Serum Protein Electrophoresis screen for?
B cell malignancy
Immunodeficiency
What are the features of the FREELITE assay?
Specific for free light chains
Quantitative
Nephelomyeric
What are the features of immunofixation electrophoresis?
Identified paraprotein type
Not quantitative
Gives prognostic information
What are the disadvantages of urine electrophoresis in the detection of monoclonal light chains?
Affected by renal function
Insensitive
24 hour urine collection is difficult
Time consuming and subjective
What are the advantages of the serum free light chain assay in the detection of monoclonal light chains?
Sensitive assay kappa/gamma ratio little affected by renal function Easy to collect Quick Quantitative
What is calcitonin and what is it used for?
Plays an important role in the pathway and regulation of calcium and phosphate in bone metabolism
The main medullary thyroid carcinoma tumour makrer
What are the advantages of PCT?
Early and high specific increase in response to severe systemic bacterial infection and sepsis
Excellent negative predictor
PCT levels can be observed from 2 hours after bacterial challenge
Accurately reflect the progression of the disease correlating more closely to severity than any other sepsis marker
Ideal for daily measurement
Can be used as a tool to discontinue empiric antibiotic therapy by individualising a patient’s treatment
What are the reference ranges of procalcitonin?
0.5-2 - Sepsis possible, antibiotics recommended reassess in under 24 hours
>2-10 - Sepsis infection likely, antibiotics recommended
>10 - Major sepsis, antibiotics recommended
