Lecture 5

Question 1

Synovial fluid

Answer 1

often referred to as “joint fluid,” is a viscous liquid found in the cavities of the movable joints.
The bones in the joints are lined with smooth cartilage and separated by a cavity containing the synovial fluid.
Synovial fluid is formed as an ultrafiltrate of plasma

Question 2

Function of Synovial fluid

Answer 2

The cartilage and synovial fluid reduce friction between the bones during joint movement.

To providing lubrication in the joints.

To providing nutrients to the cartilage.

Lessens the shock to joints during activities such as walking and jogging.

Question 3

Why is Synovial Fluid Tested

Answer 3

The test can help diagnose the cause of pain, redness, or swelling in joints.
Sometimes, removing the fluid can also help relieve (remove) joint pain.
Synovial fluid is tested when a doctor suspects:
Different types of arthritis
Bleeding in the joint after a joint injury
Gout
Infection in a joint

Question 4

Specimen Collection and Handling -Synovial Fluid

Answer 4

Synovial fluid is collected by needle aspiration
The amount of fluid present in normal knee cavity is about 2-4 mls but can increase to greater than 25 mL with inflammation.
Normal synovial fluid does not clot; however, fluid from a diseased joint may contain fibrinogen and will clot., collected in EDTA tubes

Question 5

Synovial Fluid - Lab Tests

Answer 5

Examine volume( 0.5 – 4.0 mls) depending on the site, colour and clarity (clear and colorless) and viscosity

Lab tests: 1) crystals- uric acid crystals 2) glucose – low possible infection 3) proteins – high indicate infection 4) uric acid, lactate dehydrogenase (LDH) elevated in people with rheumatoid arthritis or infection arthritis 5) cell count 6) gram stain and culture & sensivity - infection

Question 6

Serous fluid

Answer 6

Serous fluid is contained between the membranes that surround all the various body organs
Body cavities
Pericardial cavity – around the heart
Pleural cavity - lungs (thoracic fluid) – lung cavity
Peritoneal cavity – abdominal (ascitic fluid) – abdominal cavity
Function of Serous Fluids
acts as lubricant
provide nutrients
remove waste

Question 7

Reasons for analysis -Serous fluid

Answer 7

Infections
Inflammation
Hemorrhages
Malignancies and other disorders.

Question 8

how to collect -Serous fluid

Answer 8

Needle aspiration
Paracentesis
Thoracentesis
Pericardiocentesis

EDTA tube for cell count & differential
Heparin tube for chemistries, serology, microbiology and cytology.

Question 9

Serous Fluids - Testing overview

Answer 9

Large volumes are usually collected – over 100 mL
Appearance - clear, pale, straw colour
Variety of tests used to aid in determining the cause of the effusion
Appearance
Clotting ability whether a clot will form or not
Cell counts
Protein
Glucose
Amylase
LDH
Culture & Sensitivity
Cytology / Pathology – if malignancy is suspected.

Question 10

Amniotic fluid

Answer 10

Amniotic fluid is a product of fetal metabolism
Tested to identify metabolic disorders of the fetus and fetal maturity
Contains small number of fetal cells that can be used for cytogenetic studies – check for genetic defects
Collection of fluid is called amniocentesis
Collected from the amniotic sac through the abdominal wall – protect from light

Question 11

Seminal Fluid

Answer 11

Sperm count for fertility
Count for vasectomy outcome
In-vivo or in-vitro fertilization, etc.

Question 12

Blood Glucose

Answer 12

Glucose is the main carbohydrate in blood and the primary source of energy for body cells
It is absorbed by body cells with the intervention of the hormone insulin
Glucose level in the body is controlled by insulin

Question 13

Insulin

Answer 13

a hormone produced by the beta cells of the pancreas
During an activity - Increase in cellular uptake of glucose and the rate of glycolysis increases to produce energy
Several hours after a meal, the blood sugar level goes down and Glucagon produced by the Alpha cells of the pancreas signals the liver and muscle to change stored glycogen back into glucose - look at the slide
(Pancreas also produce digestive enzymes)

Question 14

Goals of Glucose Regulation or Homestatis

Answer 14

Get glucose into cells for utilization/storage
Glucose is primary fuel for cellular energy
Can be stored in liver and muscles as glycogen

Breakdown stored energy into glucose
Glycogen breakdown can quickly supply glucose
Lipids and proteins can be converted to glucose

Keep blood glucose from becoming too low or too high
 Hypo- and hyperglycemia can both be dangerous

Question 15

Disorders of glucose metabolism

Answer 15

Diabetes mellitus / hyperglycemia
Persistent high blood glucose levels
Common disease in today’s population
Failure to control blood sugar levels
Hypoglycemia
Decreased blood glucose

Question 16

Hyperglycemia Diabetes mellitus

Answer 16

Too much glucose in blood
Malfunction in insulin pathway either the pancreas or the tissue cells
Chronic hyperglycemia carries several long term effects:
Increased risk of cardiovascular disease and stroke
Frequent hunger, thirst, and need for urination
Tissue damage (e.g., retina, kidneys)
Ketoacidosis

Growth hormone, cortisol – can also increase blood glucose

Question 17

Hypoglycemia

Answer 17

Too little glucose in blood
A number of potential causes:
Improper insulin dosage in diabetes patients
Over secretion of bodily insulin
Hormone (glucagon) deficiency
Long-term fasting
Liver dysfunction due to alcohol
This is a medical emergency
CNS requires continuous supply of glucose
Even brief denial of glucose to brain can cause long-term damage

Question 18

Glucose test - chemistry

Answer 18

random or fasting
Glucose measurement can be performed on:
Whole blood, plasma, serum, urine, CSF, body fluids
Most laboratories measure serum/plasma glucose levels
Separate serum/plasma from cells ASAP
Prolonged exposure to blood cells will lead to excessive glycolysis in the sample. Result in false low glucose value. Blood cells metabolize glucose
Collect samples in a grey top tube. Potassium oxalate anticoagulant. Sodium fluoride to inhibit glycolysis
Serum separator tubes also preserve glucose in samples after being centrifuged
Serum isolated from the cells

Arterial, venous and capillary blood have comparable glucose levels in a fasting individual
Delay in testing – separate and refrigerate the serum
Separate serum/plasma from cells

Question 19

Principle of Testing

Answer 19

Testing methods use the enzymes –
Glucose oxidase, hexokinase or glucose dehydrogenase
These enzyme tests are specific for glucose
Used in glucose analytical methods
The reagent strips utilize glucose oxidase

Reference range Fasting Blood Glucose: 3.9 – 6.1 mmol/L

Question 20

Diagnostic Tests- glucose

Answer 20

Diabetes (Hyperglycemia) and Hypoglycemia
Random (blood, urine)

Fasting Blood Glucose
2 hour Post Consumption (2 hr pc)
Tolerance Test
HbA1c

Question 21

Fasting Blood Glucose (Sugar) – FBS

Answer 21

Patient fasting for approximately (8 – 12 hrs)
Allowed to have sips of water only
Blood Glucose is tested on fasting sample
Most commonly used as an indicator of overall glucose homeostasis
Largely because food intake is avoided

Question 22

Oral) Glucose Tolerance Test – OGTT

Answer 22

A medical test in which glucose is given to a patient, and blood samples taken afterward to determine how quickly the glucose is cleared from the blood
Five blood and urine samples at prescribed times before and after the intake of a standardized amount of oral glucose
OGTT measures the response of the body to a challenge/bolus load of glucose in aiding the diagnosis of diabetes mellitus

Question 23

Testing OGTT

Answer 23

Require a FBS and a urine sample
Patient consumes a glucose drink
50, 75, or 100 g glucose dose
75 gms of glucose is given to an adult and 50 gms to a woman who is pregnant
75g glucose in 300 mL solution most often given
Usually consumed within 5 minutes
Blood and urine samples are collected at 30 minutes, 1, 2, 3 hours after consuming the drink
2 & 3 hour test sometimes used for diabetes – glucose should level off and be near normal after 2 hr
Difficult to administer – requiring much time and repeated blood tests

Question 24

Critical Values:

Answer 24

Glucose < 2.2 mmol/L

Glucose > 22.2 mmol/L

Question 25

Reference Ranges: (measured in mmol/L)

Answer 25

Fasting: 3.9 – 6.1 mmol/L
Diabetes: < 7 mmol/L (fasting)
Random – up to 7.8 mmol/L

Question 26

Hemoglobin A1c (HbA1c)

Answer 26

Also called glycosylated (glycated) hemoglobin
Protein in RBC that carries oxygen is coated with glucose (glycated)
Need EDTA blood
When blood glucose levels are high, glucose molecules enter the RBC and combine with Hb, to form HbA1c
The higher the Hb A1c the poorer the blood sugar control
Measurement indicates how the body controls blood glucose levels for the past 2-3 months
Hemoglobin A1c test is done every three months on diabetic patients

Normal value is less than 6%
For diabetes control – less than 7%

Question 27

Diagnosis - Diabetes

Answer 27

Recurring or persistent hyperglycemia
Fasting serum/plasma glucose level ≥7.0mmol/L
Plasma/serum glucose ≥11.1mmol/L two hours after a GTT is diagnosic of diabetes

Hb A1c ≥6.5%

Positive urinalysis test for uncontrolled diabetes – Glucose and ketone

Question 28

Symptoms of diabetes

Answer 28

High blood sugar produce the classical symptoms of: 
Frequent urination (polyuria)
Increased thirst 
Increased hunger
Blurry vision
Wounds that don't heal

Question 29

Diabetes Mellitus

Answer 29

Commonly called diabetes
A chronic metabolic disorder associated with a deficiency of insulin
Resulting in an inability of the body to handle glucose
Insulin unlock the cells of the body to enable glucose to enter and become fuel for the cells
Instead of moving glucose into the cells, sugar builds up in the blood stream
As the blood sugar increases, the beta cells in the pancreas release more insulin but eventually these cells become impaired (exhausted) and cannot make enough insulin to meet the body’s needs

Question 30

Type1 diabetes

Answer 30

Juvenile diabetes - results from the body’s failure to produce insulin. Immune system destroys the beta cells in the pancreas leaving the body with little or no insulin
Usually diagnosed in children and young adults
Requires insulin injection

Question 31

Type2 diabetes:

Answer 31

also known as insulin resistance
Occurs later in life - called adult-onset diabetes
A condition in which cells fail to use insulin properly

Question 32

Gestational diabetes:

Answer 32

pregnant women, who have never had diabetes before
Have a high blood glucose level during pregnancy
GTT is done at 6 weeks and at 6 months(Note: Pregnant woman are given 50gms of oral glucose)
High glucose level in pregnant women if not controlled can lead to malformation of the fetus or still born births