L1 Basic concepts - result interpretation

Pink or reddish.

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

The insolubility of monoclonal proteins in low ionic strength conditions.

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.

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

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

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

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.

Hemolysis, icteric, and turbidity.

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

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

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

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

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

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

Higher hemoglobin levels in serum correlate with higher LDH levels.

Potassium ↑, Phosphate ↑, Glucose ↓, ACTH ↓

Potassium ↑

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

10 years (215 - 476 U/L)

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

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.

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

Lactation and breast development.

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

To avoid misdiagnosis, unnecessary investigations, and treatment.

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

PEG precipitation and ultrafiltration (UF).

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

All abnormal results must be repeated and validated.

To separate serum from blood cells using a separator gel.

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

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

Heparinized syringe, sent on ice.

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

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).

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).

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

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

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

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

Forcing blood into the tube may cause hemolysis.

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

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.

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

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.

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

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

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

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

Hemolysis can cause an increase in potassium levels.

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

Bias = Test sample result – Baseline sample result.

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

Separator Gel.

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.

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

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

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

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

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

Hyperuricemia, hyperphosphatemia, hyperkalemia, and hypocalcemia.

Serum and Clot.

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

An appropriate diluent suggested by the manufacturer should be used.

Hemolysis increases LDH test results significantly.

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

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

149 - 369 U/L

The age of patients.

Potassium test results increase as hemoglobin levels increase.

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

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

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

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

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

Hematologic malignancies such as acute lymphoblastic leukemia (ALL).

Potassium ↑, Phosphate ↑, AST ↑, LDH ↑

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.

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

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

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

Males have higher plasma creatinine levels than females.

They cause artefactually increased enzyme or hormone results.

Because it inhibits glycolysis.

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

Deoxyhaemoglobin, oxyhaemoglobin, and carboxyhaemoglobin.

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

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.

Progesterone and Estrogen.

Prolactin.

Heparinized plasma, but serum is also acceptable.

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

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

Hemolytic, icteric, and lipemic samples.

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

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

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.