What color does hemolyzed serum or plasma typically have?
Pink or reddish.
What was the mean LDH result for a hemoglobin level of 1.6 g/dL?
1633.50 U/L
1/100
p.29
Impact of Hemolysis, Icteric, and Lipemic Samples

What color does hemolyzed serum or plasma typically have?

Pink or reddish.

p.8
Impact of Hemolysis, Icteric, and Lipemic Samples

What was the mean LDH result for a hemoglobin level of 1.6 g/dL?

1633.50 U/L

p.31
Physiological Variations Affecting Test Results

What is tumor lysis syndrome?

A condition characterized by the rapid lysis of malignant cells after chemotherapy, leading to the release of cellular components into the blood.

p.2
Protein Precipitation Interferences

What principle is the Sia water test based on?

The insolubility of monoclonal proteins in low ionic strength conditions.

p.16
Physiological Variations Affecting Test Results

How does posture affect the concentration of proteins and protein-bound substances in the blood?

In an upright position, the increase in hydrostatic pressure causes a relative increase in the concentrations of proteins and protein-bound substances such as calcium, steroid, and thyroid total hormones.

p.9
Sample Collection and Handling Errors

How is carry-over tested in analyzers?

By running a sample with high analyte level 3 times, followed by running a sample with low analyte level 3 times.

p.4
Sample Dilution Techniques and Best Practices

What is a common solution to mitigate the hook effect in immunoassays?

Diluting the sample to bring the antigen concentration within the assay's optimal range.

p.37
Sample Dilution Techniques and Best Practices

Why is sample dilution considered a high-risk process?

Because errors can easily occur, such as using inappropriate diluents or incorrect dilution factors.

p.35
Sample Dilution Techniques and Best Practices

How do you prepare a 1:10 dilution of serum?

Add 100 microlitres (μL) of serum to 900 μL of appropriate diluent (e.g., saline) or add 20 μL of serum to 180 μL of saline.

p.6
Types of Interference in Laboratory Testing

What are the three types of interference studied in laboratory testing?

Hemolysis, icteric, and turbidity.

p.30
Physiological Variations Affecting Test Results

How does thrombocytosis affect potassium levels in blood samples?

Thrombocytosis causes the release of potassium from platelets during coagulation, resulting in pseudohyperkalemia.

p.34
Sample Collection and Handling Errors

What should be done to understand abnormal results besides repeating the test?

The root cause of the abnormal results should be found out.

p.14
Detection Methods for Protein Interference

What are common methods to detect macromolecules?

Polyethylene glycol (PEG) precipitation, ultrafiltration (UF), electrophoresis, and gel filtration chromatography (GFC).

p.33
Impact of Hemolysis, Icteric, and Lipemic Samples

What was the likely cause of the abnormal results in the first blood sample of the young male patient?

K-EDTA contamination, which caused low calcium due to chelation by EDTA and low alkaline phosphatase (AP) due to chelation of magnesium and zinc.

p.11
Macroenzymes and Their Clinical Significance

What might indicate macromolecule interference if symptoms do not align with the magnitude of enzyme or hormone increase?

Symptoms that do not align with the magnitude of increase of enzyme or hormone may indicate macromolecule interference.

p.33
Impact of Hemolysis, Icteric, and Lipemic Samples

Why was alkaline phosphatase (AP) low in the first blood sample?

AP was low because EDTA chelates magnesium and zinc, and magnesium is a cofactor for AP activity.

p.8
Impact of Hemolysis, Icteric, and Lipemic Samples

How does the presence of hemoglobin in serum affect LDH levels?

Higher hemoglobin levels in serum correlate with higher LDH levels.

p.32
Sample Collection and Handling Errors

What are the effects of a delay in processing samples?

Potassium ↑, Phosphate ↑, Glucose ↓, ACTH ↓

p.32
Sample Collection and Handling Errors

How does temperature affect sample results when stored overnight in a fridge or in cold weather?

Potassium ↑

p.18
Physiological Variations Affecting Test Results

Why is it important to consider diurnal variations in clinical testing?

Considering diurnal variations is important to ensure accurate and consistent test results, as some biomarkers may vary significantly throughout the day.

p.17
Physiological Variations Affecting Test Results

At what age do females have the highest reference range for plasma alkaline phosphatase (AP)?

10 years (215 - 476 U/L)

p.12
Macroenzymes and Their Clinical Significance

What are the mechanisms of formation for Macroenzyme type 2?

Binding of enzymes to foreign substances in blood (e.g., drugs) and self-polymerization.

p.27
Impact of Hemolysis, Icteric, and Lipemic Samples

What causes hemolysis and what are its effects on laboratory results?

Hemolysis is the lysis of red blood cells (RBCs), causing the release of potassium, magnesium, phosphate, and lactate dehydrogenase (LD). Lysis of white blood cells (WBCs) and platelets also releases potassium but to a lesser extent.

p.35
Sample Dilution Techniques and Best Practices

Why are sample dilutions often required in laboratory testing?

Sample dilutions are often required when the tested analyte exceeds the analytical range of the method.

p.13
Macroenzymes and Their Clinical Significance

What is prolactin responsible for?

Lactation and breast development.

p.13
Macroenzymes and Their Clinical Significance

What is macroprolactin?

A complex of immunoglobulin G and prolactin with little biological activity in vivo.

p.13
Macroenzymes and Their Clinical Significance

Why is lab diagnosis important in cases of macroprolactin?

To avoid misdiagnosis, unnecessary investigations, and treatment.

p.30
Physiological Variations Affecting Test Results

What is a potential cause of pseudohyperkalemia in patients with extreme leukocytosis?

In vitro release of potassium from leukocytes undergoing lysis during the clotting process.

p.4
Endogenous and Exogenous Interferences in Immunoassays

How does the hook effect impact immunoassay results?

It causes falsely low results due to the saturation of antibodies by an excess of antigen.

p.14
Detection Methods for Protein Interference

Which methods are most accessible and straightforward for detecting macromolecules?

PEG precipitation and ultrafiltration (UF).

p.28
Types of Interference in Laboratory Testing

Why is it important to consider spectral interference when measuring hemoglobin levels?

Because the overlapping absorption spectra of deoxyhaemoglobin, oxyhaemoglobin, and carboxyhaemoglobin can lead to inaccurate results.

p.34
Sample Collection and Handling Errors

What must be done with all abnormal results in laboratory testing?

All abnormal results must be repeated and validated.

p.23
Sample Collection and Handling Errors

What is the purpose of a Serum Separator Tube (SST) in blood collection?

To separate serum from blood cells using a separator gel.

p.1
Protein Precipitation Interferences

What can high levels of paraproteins cause in laboratory tests?

Precipitation of method reagent due to physiochemical interactions, leading to increased turbidity of the sample.

p.15
Physiological Variations Affecting Test Results

When are adrenocorticotropic hormone (ACTH) and cortisol levels highest?

ACTH and cortisol levels are highest in the morning and lowest in the late evening.

p.24
Sample Collection and Handling Errors

What type of specimen is required for arterial blood gas analysis?

Heparinized syringe, sent on ice.

p.25
Sample Collection and Handling Errors

Why is the correct order of draw important when multiple collection tubes are needed?

To avoid contamination by incorrect anticoagulants, such as K-EDTA contamination.

p.3
Endogenous and Exogenous Interferences in Immunoassays

What is the hook effect in immunoassays and how does it affect test results?

The hook effect, or antigen excess, occurs in assays with a very wide measurement range and high test results, causing falsely low values. This is commonly seen in tumor markers like Alpha fetoprotein (AFP).

p.35
Sample Dilution Techniques and Best Practices

What is the process for making a 1:1000 dilution using serial dilutions?

First, make a 1:10 dilution (Tube 1). From Tube 1, make another 1:10 dilution to produce Tube 2 (1:100 dilution). From Tube 2, make another 1:10 dilution to produce Tube 3 (1:1000 dilution).

p.10
Macroenzymes and Their Clinical Significance

What are macromolecules in the context of laboratory testing?

High molecular weight complexes of enzymes or hormones with immunoglobulins (Igs) or less commonly with non-Ig components such as drugs.

p.2
Protein Precipitation Interferences

What is the Sia water test used for?

To detect the presence of monoclonal protein (paraprotein) interference.

p.12
Macroenzymes and Their Clinical Significance

What is Macroenzyme type 1 formed by?

By the association of enzyme with immunoglobulins (IgG, IgA, and less commonly IgM).

p.7
Impact of Hemolysis, Icteric, and Lipemic Samples

How does hemolysis affect AST (enzyme) test results?

As hemoglobin levels increase, AST test results initially increase and then become suppressed at higher hemoglobin levels.

p.25
Impact of Hemolysis, Icteric, and Lipemic Samples

Why should you not force blood into the collection tube?

Forcing blood into the tube may cause hemolysis.

p.17
Physiological Variations Affecting Test Results

Why do girls have peak AP levels earlier than boys?

Girls typically reach their peak AP levels earlier due to earlier onset of puberty and associated bone growth.

p.14
Detection Methods for Protein Interference

Describe the PEG 8000 method for detecting macromolecule interference.

Add 100 μL of PEG 8000 (250 g/L in phosphate buffered saline) to 100 μL of serum and vortex for 30 seconds. Incubate at room temperature for 10 minutes, then centrifuge at 10000 g for 5 minutes. Measure the enzyme or hormone in the PEG supernatant and in a diluted sample (100 μL serum + 100 μL saline). Calculate recovery as the enzyme activity or hormone level in the PEG supernatant divided by the enzyme activity or hormone level in the diluted sample.

p.30
Sample Collection and Handling Errors

What can cause pseudohyperkalemia, magnesium, phosphate, AST, and LD in blood samples?

Delayed separation of blood and storage of blood at 4°C before centrifugation.

p.18
Physiological Variations Affecting Test Results

How do diurnal variations affect laboratory test results?

Diurnal variations can cause significant changes in the levels of certain substances in the body, such as hormones, which can affect the accuracy of laboratory test results depending on the time of day the sample is collected.

p.2
Protein Precipitation Interferences

What are some practical solutions to detect protein interference?

Using alternate methods like dry chemistry, performing tests with different dilutions, and removing paraproteins by ultracentrifugation, dialysis, or ultrafiltration.

p.16
Physiological Variations Affecting Test Results

What is the effect of exercise on plasma enzymes?

Exercise increases the levels of plasma enzymes such as creatine kinase (CK), lactate dehydrogenase (LD), and aspartate aminotransferase (AST).

p.19
Effects of Pregnancy on Laboratory Results

How does pregnancy affect the concentration of plasma sodium?

Plasma sodium is about 3-5 mmol/L lower during pregnancy.

p.11
Macroenzymes and Their Clinical Significance

What are some signs that consistent elevation of an enzyme or hormone might be due to macromolecule interference?

Consistent elevation of an enzyme or hormone that does not resolve and lack of response to treatment might indicate macromolecule interference.

p.29
Impact of Hemolysis, Icteric, and Lipemic Samples

What is the effect of hemolysis on potassium levels in a blood sample?

Hemolysis can cause an increase in potassium levels.

p.18
Physiological Variations Affecting Test Results

What are diurnal variations?

Diurnal variations are fluctuations in biological or physiological processes that occur within a 24-hour cycle.

p.6
Detection Methods for Protein Interference

How is the bias caused by the interfering substance calculated?

Bias = Test sample result – Baseline sample result.

p.4
Endogenous and Exogenous Interferences in Immunoassays

What is the hook effect in immunoassays?

The hook effect, also known as antigen excess, occurs when extremely high levels of antigen saturate the antibodies, leading to falsely low results.

p.23
Sample Collection and Handling Errors

What component in a Serum Separator Tube (SST) helps in separating serum from blood cells?

Separator Gel.

p.11
Macroenzymes and Their Clinical Significance

When should laboratories consider the presence of macromolecule interferences?

When there are elevated enzyme or hormone results in the absence of associated signs or symptoms, such as increased serum prolactin levels without signs of hyperprolactinemia or consistently increased serum amylase without an increase in lipase.

p.19
Effects of Pregnancy on Laboratory Results

Which substances increase in concentration during pregnancy?

Thyroxine binding globulin, prolactin, estriol (E3), and human chorionic gonadotropin (hCG) increase during pregnancy.

p.20
Effects of Pregnancy on Laboratory Results

Which hormones are produced by the placenta?

hCG (human chorionic gonadotropin), Progesterone, Estriol, Prolactin, and hPL (human placental lactogen).

p.10
Macroenzymes and Their Clinical Significance

Which immunoglobulins are usually found in macromolecules?

IgG and IgA are usually found, while IgM is occasionally detected.

p.15
Physiological Variations Affecting Test Results

What is the effect of food ingestion on triglyceride concentration?

Triglyceride concentration increases immediately after meals due to the absorption of fat and formation of chylomicrons.

p.9
Sample Collection and Handling Errors

What causes carry-over in analyzers?

Contamination from a previous sample with high analyte levels, most often due to the sample probe.

p.31
Physiological Variations Affecting Test Results

What are the key biochemical abnormalities that characterize tumor lysis syndrome?

Hyperuricemia, hyperphosphatemia, hyperkalemia, and hypocalcemia.

p.23
Sample Collection and Handling Errors

What forms in a Serum Separator Tube (SST) after blood clotting?

Serum and Clot.

p.16
Physiological Variations Affecting Test Results

How does stress affect hormone levels?

Stress markedly increases the production of adrenocorticotropic hormone (ACTH), causing an increase in cortisol production, and also increases prolactin levels.

p.37
Sample Dilution Techniques and Best Practices

What should be used to dilute a sample for sodium or chloride testing instead of saline (0.90% w/v of NaCl)?

An appropriate diluent suggested by the manufacturer should be used.

p.8
Impact of Hemolysis, Icteric, and Lipemic Samples

What is the effect of hemolysis on LDH test results?

Hemolysis increases LDH test results significantly.

p.6
Sample Collection and Handling Errors

How should the sample be split for interference studies?

Split the sample into two equal portions (2 tubes).

p.34
Sample Collection and Handling Errors

Is repeating a test the same as validating it?

No, repeating the test is not the same as validating it.

p.17
Physiological Variations Affecting Test Results

What are the reference values of plasma alkaline phosphatase (AP) for males aged 4 years?

149 - 369 U/L

p.12
Macroenzymes and Their Clinical Significance

What increases the prevalence of serum macroamylase, macro-CK, and macro-LD?

The age of patients.

p.7
Impact of Hemolysis, Icteric, and Lipemic Samples

What is the trend observed in potassium (K) test results with increasing hemoglobin levels?

Potassium test results increase as hemoglobin levels increase.

p.3
Endogenous and Exogenous Interferences in Immunoassays

How do heterophile antibodies interfere in immunoassays?

Heterophile antibodies predominantly interfere in two-site immunometric (sandwich) assays by forming a bridge between capture and detection antibodies.

p.19
Effects of Pregnancy on Laboratory Results

What happens to plasma albumin, transaminases (ALT, AST), and total bilirubin levels during pregnancy?

Plasma albumin, transaminases (ALT, AST), and total bilirubin levels are low during pregnancy.

p.21
Sample Collection and Handling Errors

What effect does a prolonged tourniquet application have on blood test results?

Prolonged tourniquet application can cause artifactual hemoconcentration, leading to falsely increased levels of protein and protein-bound substances such as albumin and calcium.

p.1
Types of Interference in Laboratory Testing

What is interference in the context of laboratory testing?

A 'substance' or 'process' that falsely alters test result(s).

p.1
Protein Precipitation Interferences

What are protein precipitation interferences most commonly associated with?

Paraproteins (monoclonal immunoglobulin), mainly IgM and IgG, such as in multiple myeloma.

p.31
Physiological Variations Affecting Test Results

Which type of malignancy is most frequently associated with tumor lysis syndrome?

Hematologic malignancies such as acute lymphoblastic leukemia (ALL).

p.32
Impact of Hemolysis, Icteric, and Lipemic Samples

What are the effects of haemolysis on sample results?

Potassium ↑, Phosphate ↑, AST ↑, LDH ↑

p.3
Endogenous and Exogenous Interferences in Immunoassays

What are heterophile antibodies and where are they commonly found?

Heterophile antibodies are human anti-animal antibodies, such as human anti-mouse antibodies. They are commonly found in people working on farms, in animal laboratories, pet shop workers, or those in contact with household pets.

p.5
Endogenous and Exogenous Interferences in Immunoassays

What are some pre-treatment methods for specimens to detect heterophile antibodies?

Prior extraction by gel-filtration chromatography, precipitation with Polyethylene Glycol (PEG) 6000, use of commercial heterophilic blocking reagents, and serial dilution of the sample.

p.5
Endogenous and Exogenous Interferences in Immunoassays

How can the Hook effect be detected?

By performing serial dilutions (e.g., 1/10, 1/100, 1/1000, etc.). Non-linear results may indicate the presence of the Hook effect.

p.21
Sample Collection and Handling Errors

How does the source of the blood sample affect test results?

The source of the sample (arterial, venous, capillary blood) can cause variations in test results.

p.15
Physiological Variations Affecting Test Results

How do age and sex affect plasma creatinine levels?

Males have higher plasma creatinine levels than females.

p.10
Macroenzymes and Their Clinical Significance

What is the impact of macromolecules on enzyme or hormone test results?

They cause artefactually increased enzyme or hormone results.

p.24
Sample Collection and Handling Errors

Why is Na Fluoride-oxalate plasma used for glucose and lactic acid tests?

Because it inhibits glycolysis.

p.5
Endogenous and Exogenous Interferences in Immunoassays

What is a method to measure heterophile antibodies?

Measurement by an alternate method that uses antibodies raised from other animal species.

p.28
Types of Interference in Laboratory Testing

Which substances' absorption spectra can cause spectral interference in hemoglobin measurements?

Deoxyhaemoglobin, oxyhaemoglobin, and carboxyhaemoglobin.

p.33
Impact of Hemolysis, Icteric, and Lipemic Samples

Why was calcium low in the first blood sample?

Calcium was low due to chelation by EDTA, which is a chelator of divalent cations.

p.37
Sample Dilution Techniques and Best Practices

What are common mistakes in sample dilution?

Using inappropriate diluents, wrong dilution or dilution factor, not diluting the sample but multiplying the result by the dilution factor, or diluting the sample but not multiplying the result by the dilution factor.

p.20
Effects of Pregnancy on Laboratory Results

Which hormones are produced by the corpus luteum?

Progesterone and Estrogen.

p.20
Effects of Pregnancy on Laboratory Results

Which hormone is produced by both the placenta and the maternal pituitary?

Prolactin.

p.24
Sample Collection and Handling Errors

What type of specimen is typically used for routine tests like RFT, LFT, CP, urate, and lipid profile?

Heparinized plasma, but serum is also acceptable.

p.25
Sample Collection and Handling Errors

What is the correct method to transfer blood from a syringe to a collection tube?

Puncture the rubber stopper with the syringe needle and let the blood be drawn into the tube by the vacuum.

p.28
Types of Interference in Laboratory Testing

What is spectral interference in the context of laboratory testing?

Spectral interference occurs when the absorption spectra of different substances overlap, causing inaccuracies in measurement.

p.27
Types of Interference in Laboratory Testing

What are the most common interferences in laboratory testing?

Hemolytic, icteric, and lipemic samples.

p.7
Impact of Hemolysis, Icteric, and Lipemic Samples

At what hemoglobin level do AST test results become suppressed?

AST test results become suppressed at a hemoglobin level of 0.8 g/dL and higher.

p.27
Impact of Hemolysis, Icteric, and Lipemic Samples

How does high plasma bilirubin (icteric sample) interfere with laboratory tests?

High plasma bilirubin, often due to liver disease, can cause spectral interference near the bilirubin absorbance peak of approximately 456 nm.

p.21
Sample Collection and Handling Errors

How can intravenous fluid contamination affect blood test results?

Drawing blood from the same arm receiving intravenous fluids can cause contamination and artifactual low results of substances due to the dilution effect of the intravenous fluid. For example, saline infusion can falsely increase sodium and chloride levels while decreasing other analytes.

Study Smarter, Not Harder
Study Smarter, Not Harder