Importance of Preanalytical Phase in Laboratory Medicine

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Questions and Answers

What percentage of total errors in diagnostic laboratories are due to preanalytical errors?

50-75% (correct)

20-30%

30-40%

80-90%

What is the primary purpose of proper patient identification in the preanalytical phase?

To reduce the risk of sample mix-ups (correct)

To ensure accurate labeling of samples

To obtain a blood sample of adequate quality

To prevent sample contamination

What is the effect of traumatic venipuncture on the quality of the blood sample?

It decreases the risk of clot formation

It has no effect on the quality of the sample

It increases the risk of hemolysis (correct)

It improves the quality of the sample

Why is it important to avoid carryover of anticoagulants or other additives when collecting multiple blood tubes from the same patient?

To prevent interference with the analytical results Signup and view all the answers

What is the primary reason for the intense focus on the preanalytical phase in the last decade?

To reduce the risk of errors in laboratory medicine Signup and view all the answers

Which of the following is an example of an uncontrollable preanalytical variable?

Age of the patient Signup and view all the answers

What is the effect of preanalytical errors on the health and safety of patients?

They can jeopardize the health and safety of patients Signup and view all the answers

What is the purpose of proper handling and storage of specimens in the preanalytical phase?

To preserve the quality of the sample Signup and view all the answers

Which of the following is an example of a preanalytical variable that can be controlled?

Specimen collection technique Signup and view all the answers

What is the primary reason for the development of recommendations and standards for the preanalytical phase?

To reduce the risk of errors in laboratory medicine Signup and view all the answers

What is the main reason for the importance of the preanalytical phase in laboratory medicine?

To ensure accurate laboratory results Signup and view all the answers

The preanalytical phase only includes specimen collection and handling.

False Signup and view all the answers

What is the purpose of proper patient identification in the preanalytical phase?

To ensure that the correct patient's sample is analyzed and to prevent mix-ups Signup and view all the answers

The label on the tube must match exactly the _________ of the patient.

identity Signup and view all the answers

Match the following preanalytical variables with their descriptions:

Age = Endogenous variable EDTA = Anticoagulant of choice for hematology variables Pregnancy = Physiological variable Traumatic venipuncture = Cause of sample artefacts Signup and view all the answers

Why is it important to perform venipuncture in the most atraumatic way possible?

To obtain a blood sample of adequate quality for analysis Signup and view all the answers

The preanalytical phase is responsible for the majority of errors in diagnostic laboratories.

True Signup and view all the answers

What is an example of a specimen variable that can be controlled in the preanalytical phase?

Choice of anticoagulant and tube Signup and view all the answers

The preanalytical phase includes all those steps that occur in the practice such as specimen collection, handling, storage, and ____________ to the laboratory.

shipping Signup and view all the answers

What is the purpose of knowing uncontrollable preanalytical variables in the preanalytical phase?

To separate their effects from disease-related changes affecting laboratory results Signup and view all the answers

What is a common consequence of removing the needle while the tourniquet is still on during venipuncture?

Vein Damage Signup and view all the answers

What is the primary concern when collecting blood specimens from a patient with an IV line?

IV fluid interference with test results Signup and view all the answers

Which of the following can cause a rapid increase in the ratio of blood cells to plasma?

Tourniquet application Signup and view all the answers

What is the consequence of mixing blood specimens too vigorously?

Hemolysis Signup and view all the answers

Why is it essential to wipe away the first blood drop in capillary collection?

To prevent specimen contamination Signup and view all the answers

What is the consequence of improper fit of the needle to the syringe during blood collection?

Hemolysis Signup and view all the answers

Why is it important to avoid probing during venipuncture?

To prevent vein damage Signup and view all the answers

What is the effect of dehydration on certain blood test results?

Increased RBC, Fe, Na, and coagulation factors Signup and view all the answers

What is the consequence of squirting blood from a syringe during collection?

Hemolysis Signup and view all the answers

Why is it essential to follow proper procedures for transportation and storage of blood specimens?

To maintain specimen quality and prevent degradation Signup and view all the answers

Which of the following is affected by a patient's diet?

Glucose and lipids Signup and view all the answers

What is the consequence of collecting blood specimens in partially filled tubes?

Altered blood-to-additive ratio Signup and view all the answers

What is the effect of crying on WBC in infants?

Increased WBC Signup and view all the answers

What is the effect of exercise on certain blood test results?

Increased glucose and creatinine Signup and view all the answers

What is the effect of fever on certain hormones?

Increased insulin and cortisol Signup and view all the answers

What is the effect of smoking on WBC?

Increased WBC Signup and view all the answers

What is the effect of body position on certain blood test results?

Increased RBC and Ca Signup and view all the answers

What is the effect of pregnancy on RBC count?

Decreased RBC count Signup and view all the answers

What should be done if a patient has a history of fainting?

Ask the patient to lie down Signup and view all the answers

What should be avoided when drawing blood from a patient who has had a mastectomy?

Drawing blood from the arm on the same side of the mastectomy Signup and view all the answers

What is the ideal time frame for processing and examining hematology samples?

Within a few hours after collection Signup and view all the answers

What is the primary purpose of collecting blood samples in the basal state?

To minimize the effects of diet and exercise on test results Signup and view all the answers

Which of the following physiological variables can affect RBC counts?

Age and altitude Signup and view all the answers

What is the effect of dehydration on blood samples?

Hemoconcentration and increased enzyme levels Signup and view all the answers

Which of the following can affect cortisol levels in blood samples?

Diurnal variation and fever Signup and view all the answers

What is the purpose of refrigerating serum/plasma samples?

To slow down biochemical reactions until analysis Signup and view all the answers

Which of the following is an example of a physiological variable that can affect TSH levels?

Diurnal variation and smoking Signup and view all the answers

What is the effect of IM injections on blood samples?

CK and LDH levels Signup and view all the answers

Which of the following is a characteristic of the basal state?

A state of fasting for 12 hours Signup and view all the answers

What is the effect of altitude on RBC counts?

Increased RBC counts due to decreased oxygen levels Signup and view all the answers

What happens to blood results when a patient is dehydrated?

They are increased Signup and view all the answers

Circadian variations can affect cortisol levels.

True Signup and view all the answers

What is the effect of exercise on glucose levels?

Increased Signup and view all the answers

Fever can affect certain ______________, such as insulin levels.

hormones Signup and view all the answers

Match the following patient conditions with their effects on blood tests:

Crying = Increased WBC in infants Exercise = Increased glucose, creatinine, and total protein Fever = Increased insulin levels and cortisol levels Pregnancy = Decreased RBC count Signup and view all the answers

Smoking can affect cholesterol levels.

True Signup and view all the answers

What should be done if a patient has a history of fainting?

Ask the patient to lie down Signup and view all the answers

What should be avoided when drawing blood from a patient who has had a mastectomy?

Drawing blood from the arm on the same side of the mastectomy Signup and view all the answers

Body position can affect certain blood tests, such as __________________ and Fe.

RBC and Na Signup and view all the answers

Seizures can occur during blood collection.

True Signup and view all the answers

What is the consequence of removing the needle while the tourniquet is still on during venipuncture?

Hemoconcentration Signup and view all the answers

Drawing blood through a hematoma can cause hemolysis.

True Signup and view all the answers

What is the primary concern when collecting blood specimens from a patient with an IV line?

Contamination of the specimen with IV fluids or medications. Signup and view all the answers

The ratio of blood cells to plasma can increase rapidly due to ________ application.

tourniquet Signup and view all the answers

Match the following errors with their consequences:

Probing = Nerve damage Failure to mix properly = Clotted anticoagulated specimens Using large volume tubes with a small diameter butterfly needle = Hemolysis Signup and view all the answers

What can cause a false high potassium and low calcium levels in blood samples?

EDTA contamination Signup and view all the answers

Partially filled tubes can affect the accuracy of coagulation tests only.

False Signup and view all the answers

Specimens should be stored according to the recommended ________ and duration to preserve their integrity until analysis.

temperature Signup and view all the answers

What can happen if the tourniquet is left on for more than 1 minute during venipuncture?

Hemoconcentration can occur. Signup and view all the answers

What can prevent reflux of additive in blood collection?

Keeping the arm in a downward position Signup and view all the answers

What is the ideal time frame for processing and examining hematology samples?

Within a few hours of collection Signup and view all the answers

The basal state is influenced by gender.

True Signup and view all the answers

What is the effect of dehydration on blood samples?

Hemoconcentration, RBC, enzymes, Fe, Ca, Na Signup and view all the answers

The primary purpose of collecting blood samples in the _______________ state is to establish reference ranges on inpatients.

basal Signup and view all the answers

Match the following physiological variables with their effects on blood tests:

Age = RBC, WBC, creatinine clearance Altitude = RBC Dehydration = Hemoconcentration, RBC, enzymes, Fe, Ca, Na Diet = Glucose, lipids, electrolytes Signup and view all the answers

Smoking can affect cortisol levels in blood samples.

True Signup and view all the answers

Which of the following physiological variables can affect TSH levels?

Diurnal variation Signup and view all the answers

What is the purpose of refrigerating serum/plasma samples?

To preserve the sample until analysis Signup and view all the answers

The basal state is defined as the resting state of the body early in the morning after _______________ hours of fasting.

12 Signup and view all the answers

IM injections can affect CK and LDH levels in blood samples.

True Signup and view all the answers

Study Notes

Importance of Preanalytical Phase

The preanalytical phase is crucial in laboratory medicine, as errors in this phase can affect the analytical phase, jeopardizing patient health and safety, and increasing medical care costs.
The preanalytical phase includes steps such as specimen collection, handling, storage, and shipping to the laboratory.
Physiological variables (e.g., age, gender, pregnancy) and endogenous variables (e.g., medication, recent meals) can also impact laboratory results.

Preanalytical Errors

Preanalytical errors account for 50% to 75% of total errors in diagnostic laboratories.
The last decade has seen an increased focus on the preanalytical phase, leading to the development of recommendations and standards.

Controlling Preanalytical Variables

Some preanalytical variables, such as specimen variables, can be controlled.
A thorough knowledge of uncontrollable variables is necessary to separate their effects from disease-related changes affecting laboratory results.

Avoiding Errors

Patient Identification

Proper patient identification is essential, requiring 100% accuracy.
The label on the tube must match the patient's identification exactly.

Sample Collection

Venipuncture should be performed in the most atraumatic way possible to obtain a blood sample of adequate quality.
Traumatic venipuncture can cause sample artefacts, such as spurious hemolysis and formation of macro/micro clots.

Choice of Anticoagulant and Tube

EDTA whole blood is the specimen of choice for most hematology variables.
When collecting multiple blood tubes, carryover of anticoagulants or additives should be avoided.
Follow the correct order of collection to avoid contamination by EDTA, which can cause false elevations of potassium and false decreases of calcium.
Serum gel separator tubes can be used for most biochemical analysis, but should be avoided for hormones and drugs measurements.

Importance of Preanalytical Phase

The preanalytical phase is crucial in laboratory medicine, as errors in this phase can affect the analytical phase, jeopardizing patient health and safety, and increasing medical care costs.
The preanalytical phase includes steps such as specimen collection, handling, storage, and shipping to the laboratory.
Physiological variables (e.g., age, gender, pregnancy) and endogenous variables (e.g., medication, recent meals) can also impact laboratory results.

Preanalytical Errors

Preanalytical errors account for 50% to 75% of total errors in diagnostic laboratories.
The last decade has seen an increased focus on the preanalytical phase, leading to the development of recommendations and standards.

Controlling Preanalytical Variables

Some preanalytical variables, such as specimen variables, can be controlled.
A thorough knowledge of uncontrollable variables is necessary to separate their effects from disease-related changes affecting laboratory results.

Avoiding Errors

Patient Identification

Proper patient identification is essential, requiring 100% accuracy.
The label on the tube must match the patient's identification exactly.

Sample Collection

Venipuncture should be performed in the most atraumatic way possible to obtain a blood sample of adequate quality.
Traumatic venipuncture can cause sample artefacts, such as spurious hemolysis and formation of macro/micro clots.

Choice of Anticoagulant and Tube

EDTA whole blood is the specimen of choice for most hematology variables.
When collecting multiple blood tubes, carryover of anticoagulants or additives should be avoided.
Follow the correct order of collection to avoid contamination by EDTA, which can cause false elevations of potassium and false decreases of calcium.
Serum gel separator tubes can be used for most biochemical analysis, but should be avoided for hormones and drugs measurements.

Hematology Samples

Hematology samples should be processed and examined immediately, ideally within a few hours of collection.
Samples sent to an external laboratory should be refrigerated.

Biochemistry Testing

Serum/plasma should be separated and transferred into a plain tube and kept at refrigeration temperature until analysis.
For longer storage, freezing is recommended.

Normal Range

A range of normal values for healthy individuals.
Influenced by age, gender, and body conditions.

Basal State

Defines the resting state of the body early in the morning after fasting for 12 hours.
Ideal for establishing reference ranges on inpatients.
Minimizes effects of diet, exercise, etc. on test results.

Physiological Variables

Factors that affect blood test results, including:
- Age: RBC, WBC, creatinine clearance
- Altitude: RBC
- Dehydration: Hemoconcentration, RBC, enzymes, Fe, Ca, Na
- Diet: Glucose, lipids, electrolytes
- Diurnal/circadian variation: TSH, cortisol, Fe
- Drug therapy: Enzymes, hormones
- Exercise: pH, PCO2, CK, LDH, glucose
- Fever: Hormones, cortisol
- Sex: RBC, Hgb, Hct
- IM injection: CK, LDH
- Jaundice: Yellow color interferes
- Position: Protein, K
- Pregnancy: RBC
- Smoking: Chol, cortisol, glucose, GH, triglyceride, WBC
- Stress: WBC, Fe, ACTH, catecholamine, cortisol
- Environmental factors: Hemoconcentration

Patient Complications and Conditions

Factors that impact blood collection and test results, including:
- Adhesive allergy
- Excessive bleeding
- Fainting
- Pain
- Seizures
- Mastectomy
- Paralysis

Procedural Errors

Mistakes during blood collection that can compromise sample quality, including:
- Hematoma
- Iatrogenic anemia
- Nerve damage
- Reflux of additive
- Vein damage

Specimen Quality Concerns

Issues that affect the integrity and reliability of blood samples, including:
- Hemoconcentration
- Hemolysis
- Partially filled tubes
- Specimen contamination
- Wrong order
- Clotted anticoagulated specimens
- IV lines
- Wrong or expired collection tube
- Transportation delays
- Storage conditions

Importance of Education

Educational programs can reduce sample errors and improve patient safety and health system outcomes.

Hematology Samples

Hematology samples should be processed and examined immediately, ideally within a few hours of collection.
Samples sent to an external laboratory should be refrigerated.

Biochemistry Testing

Serum/plasma should be separated and transferred into a plain tube and kept at refrigeration temperature until analysis.
For longer storage, freezing is recommended.

Normal Range

A range of normal values for healthy individuals.
Influenced by age, gender, and body conditions.

Basal State

Defines the resting state of the body early in the morning after fasting for 12 hours.
Ideal for establishing reference ranges on inpatients.
Minimizes effects of diet, exercise, etc. on test results.

Physiological Variables

Factors that affect blood test results, including:
- Age: RBC, WBC, creatinine clearance
- Altitude: RBC
- Dehydration: Hemoconcentration, RBC, enzymes, Fe, Ca, Na
- Diet: Glucose, lipids, electrolytes
- Diurnal/circadian variation: TSH, cortisol, Fe
- Drug therapy: Enzymes, hormones
- Exercise: pH, PCO2, CK, LDH, glucose
- Fever: Hormones, cortisol
- Sex: RBC, Hgb, Hct
- IM injection: CK, LDH
- Jaundice: Yellow color interferes
- Position: Protein, K
- Pregnancy: RBC
- Smoking: Chol, cortisol, glucose, GH, triglyceride, WBC
- Stress: WBC, Fe, ACTH, catecholamine, cortisol
- Environmental factors: Hemoconcentration

Patient Complications and Conditions

Factors that impact blood collection and test results, including:
- Adhesive allergy
- Excessive bleeding
- Fainting
- Pain
- Seizures
- Mastectomy
- Paralysis

Procedural Errors

Mistakes during blood collection that can compromise sample quality, including:
- Hematoma
- Iatrogenic anemia
- Nerve damage
- Reflux of additive
- Vein damage

Specimen Quality Concerns

Issues that affect the integrity and reliability of blood samples, including:
- Hemoconcentration
- Hemolysis
- Partially filled tubes
- Specimen contamination
- Wrong order
- Clotted anticoagulated specimens
- IV lines
- Wrong or expired collection tube
- Transportation delays
- Storage conditions

Importance of Education

Educational programs can reduce sample errors and improve patient safety and health system outcomes.

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Description

Learn about the preanalytical phase in laboratory medicine, its impact on patient health and safety, and the variables that can affect laboratory results.