Ablood testis alaboratoryanalysis performed on abloodsample that is usually extracted from aveinin the arm using ahypodermic needle,or viafingerprick.Multiple tests for specific blood components, such as aglucose testor acholesterol test,are often grouped together into onetest panelcalled ablood panelorblood work.Blood tests are often used inhealth careto determinephysiologicalandbiochemicalstates, such asdisease,mineralcontent,pharmaceutical drugeffectiveness, and organ function. Typicalclinicalblood panels include abasic metabolic panelor acomplete blood count.Blood tests are also used indrug teststo detect drug abuse.
Extraction
edit
Avenipunctureis useful as it is aminimally invasiveway to obtaincellsandextracellular fluid(plasma) from the body for analysis. Blood flows throughout the body, acting as a medium that providesoxygenand nutrients to tissues and carries waste products back to the excretory systems for disposal. Consequently, the state of the bloodstream affects or is affected by, many medical conditions. For these reasons, blood tests are the most commonly performedmedical tests.[1]
If only a few drops of blood are needed, afingerstickis performed instead of avenipuncture.[2]
Indwelling arterial, central venous and peripheral venous lines can also be used to draw blood.[3]
Phlebotomists,laboratory practitionersandnursesare those in charge of extracting blood from a patient. However, in special circumstances, and/or emergency situations,paramedicsandphysiciansextract the blood. Also,respiratory therapistsare trained to extract arterial blood to examinearterial blood gases.[4][5]
Types of tests
edit
Biochemical analysis
editAbasic metabolic panelmeasuressodium,potassium,chloride,bicarbonate,blood urea nitrogen(BUN),magnesium,creatinine,glucose,and sometimescalcium.Tests that focus on cholesterol levels can determineLDLandHDL cholesterollevels, as well astriglyceridelevels.[6]
Some tests, such as those that measure glucose or alipid profile,require fasting (or no food consumption) eight to twelve hours prior to the drawing of the blood sample.[7]
For the majority of tests, blood is usually obtained from the patient's vein. Other specialized tests, such as thearterial blood gastest, require blood extracted from anartery.Blood gas analysis of arterial blood is primarily used to monitorcarbon dioxideandoxygenlevels related topulmonaryfunction, but is also used to measure bloodpHandbicarbonatelevels for certain metabolic conditions.[8]
While the regularglucose testis taken at a certain point in time, theglucose tolerance testinvolves repeated testing to determine the rate at whichglucoseis processed by the body.[9]
Blood tests are also used to identify autoimmune diseases andImmunoglobulin E-mediated food allergies (see alsoRadioallergosorbent test).[10]: 1118
Normal ranges
editBlood tests results should always be interpreted using the ranges provided by the laboratory that performed the test. Example ranges are shown below.
| Test[11][12] | Low | High | Unit | Comments |
|---|---|---|---|---|
| Sodium(Na) | 134 | 145 | mmol/L | |
| Potassium(K) | 3.5 | 5.0 | mmol/L | |
| Urea | 2.5 | 6.4 | mmol/L | Blood urea nitrogen(BUN) |
| Urea | 15 | 40 | mg/dL | |
| Creatinine- male | 62 | 115 | μmol/L | |
| Creatinine - female | 53 | 97 | μmol/L | |
| Creatinine - male | 0.7 | 1.3 | mg/dL | |
| Creatinine - female | 0.6 | 1.2 | mg/dL | |
| Glucose(fasting) | 3.9 | 5.8 | mmol/L | See alsoglycated hemoglobin |
| Glucose (fasting) | 70 | 120 | mg/dL |
Common abbreviations
editUpon completion of a blood test analysis, patients may receive a report with blood test abbreviations. Examples of common blood test abbreviations are shown below.
| Abbreviation[13][14] | Stands for | Description |
|---|---|---|
| HDL | High Density Lipoprotein | Level of "good cholesterol" in the blood (ratio of HDL:LDL is usually more significant than actual values) |
| LDL | Low Density Lipoprotein | Level of "bad cholesterol" in the blood (ratio of HDL:LDL is usually more significant than actual values) |
| PV | Plasma Viscosity | Plasma Viscometry (PV) is the measurement of the viscosity of blood plasma. The result is a number given in milliPascal seconds (m.Pas.s) – known as the PV, or plasma viscosity. |
| CRP | C-Reactive Protein | Level of inflammation with the body. If the immune system is fighting an infection or illness, CRP will be higher. |
| CBC
(UK: FBC) |
Complete Blood Count
(UK: Full Blood Count) |
Analysis of 15 different blood test readings to provide information about overall health. |
| TSH | Thyroid-stimulating hormone | Thyroid regulates the function of metabolism. Low levels can lead to weight loss, while high levels lead to weight gain. |
| PTH | Parathyroid hormone | Regulatesserum calcium |
| ESR | Erythrocyte Sedimentation Rate | Indicates the time it takes for red blood cells to move down a tube. This shows signs of inflammation within a body. |
| INR | International Normalized Ratio | This is a blood clotting test. |
| LFT | Liver Function Test | This test reveals the levels of waste products, enzymes and proteins that are processed by the liver. |
| U+E | Urea and Electrolytes | This test is performed to measure the function of kidney. |
| CMP | Comprehensive Metabolic Panel | This analysis provides an overall picture of the metabolism and chemical balance of the body. |
| WBC | White Blood CellCount | The level of white blood cells. |
| RBC | Red Blood CellCount | The level of red blood cells. |
| HBC | Hemoglobin | Level of hemoglobin molecules. |
| HCT | Hematocrit | Similar to RBC but in percentage. |
| PLT | Platelets | Platelets levels in the blood. |
Molecular profiles
edit- Protein electrophoresis(general technique—not a specific test)
- Western blot(general technique—not a specific test)
- Liver function tests
- Polymerase chain reaction(DNA).DNA profilingis today possible with even very small quantities of blood: this is commonly used inforensic science,but is now also part of the diagnostic process of many disorders.
- Northern blot(RNA)
- Sexually transmitted diseases
Cellular evaluation
edit- Full blood count(or "Complete Blood Count" )
- Hematocrit
- MCV( "Mean Corpuscular Volume" )
- Mean corpuscular hemoglobin concentration(MCHC)
- Erythrocyte sedimentation rate(ESR)
- Cross-matching.Determination ofblood typeforblood transfusionortransplants
- Blood culturesare commonly taken if infection is suspected. Positive cultures and resulting sensitivity results are often useful in guiding medical treatment.
Future alternatives
editSaliva tests
editIn 2008, scientists announced that the more cost effectivesaliva testingcould eventually replace some blood tests, as saliva contains 20% of the proteins found in blood.[15]Saliva testing may not be appropriate or available for all markers. For example, lipid levels cannot be measured with saliva testing.
Microemulsion
editIn February 2011, Canadian researchers at the University of Calgary's Schulich School of Engineering announced a microchip for blood tests. Dubbed a microemulsion, a droplet of blood captured inside a layer of another substance. It can control the exact size and spacing of the droplets. The new test could improve the efficiency, accuracy, and speed of laboratory tests while also doing it cheaply.[16]
SIMBAS
editIn March 2011, a team of researchers fromUC Berkeley,DCUandUniversity of Valparaísohave developedlab-on-a-chipthat can diagnose diseases within 10 minutes without the use of external tubing and extra components. It is called Self-powered Integrated Microfluidic Blood Analysis System (SIMBAS). It uses tiny trenches to separate blood cells from plasma (99 percent of blood cells were captured during experiments). Researchers used plastic components, to reduce manufacturing costs.[17][18]
See also
edit- Barbro Hjalmarsson
- Biomarker (medicine),a protein or other biomolecule measured in a blood test
- Blood film,a way to look at blood cells under a microscope
- Blood gas test
- Blood lead level
- Hematology,the study of blood
- Luminol,a visual test for blood left at crime scenes.
- Reference ranges for blood tests
- Schumm test,a common test for blood mismatch
- Category:Blood tests
- List of medical tests
References
edit- ^"Venipuncture - the extraction of blood using a needle and syringe".Archivedfrom the original on June 21, 2012.RetrievedJune 21,2012.
- ^MacLennan CA, van Oosterhout JJ, White SA, Drayson MT, Zijlstra EE, Molyneux ME (July 2007)."Finger-prick blood samples can be used interchangeably with venous samples for CD4 cell counting indicating their potential for use in CD4 rapid tests".AIDS.21(12): 1643–5.doi:10.1097/QAD.0b013e32823bcb03.PMC2408852.PMID17630562.
- ^Lesser, Finnian D; Lanham, David A; Davis, Daniel (6 May 2020)."Blood sampled from existing peripheral IV cannulae yields results equivalent to venepuncture: a systematic review".JRSM Open.11(5): 205427041989481.doi:10.1177/2054270419894817.PMC7236571.PMID32523703.
- ^Aaron SD, Vandemheen KL, Naftel SA, Lewis MJ, Rodger MA (2003)."Topical tetracaine prior to arterial puncture: a randomized, placebo-controlled clinical trial".Respir. Med.97(11): 1195–1199.doi:10.1016/S0954-6111(03)00226-9.PMID14635973.
- ^"Michigan careers".Michigan.gov. 2010-01-05. Archived fromthe originalon June 29, 2011.Retrieved2011-08-09.
- ^Belargo, Kevin."Cholesterol Levels".Manic EP.Archivedfrom the original on 18 January 2012.Retrieved17 January2012.
- ^"Fasting blood samples".NHS UK.Archivedfrom the original on June 21, 2012.RetrievedJune 21,2012.
- ^"Blood gases".NHS UK.Archivedfrom the original on May 6, 2012.RetrievedJune 21,2012.
- ^"Glucose tolerance test".Medline.Archivedfrom the original on June 9, 2012.RetrievedJune 21,2012.
- ^Handbook of nutrition and food.Carolyn D. Berdanier, Johanna T. Dwyer, Elaine B. Feldman (2 ed.). Boca Raton: Taylor & Francis. 2008.ISBN978-0-8493-9218-4.OCLC77830546.
{{cite book}}:CS1 maint: others (link) - ^C. A. Burtis and E. R. Ashwood,Tietz Textbook of Clinical Chemistry(1994) 2nd edition,ISBN0-7216-4472-4
- ^"Blood tests normal ranges".Monthly Prescribing Reference.Archivedfrom the original on June 21, 2018.RetrievedJune 21,2012.
- ^"Appendix B: Some Common Abbreviations".MedlinePlus.U.S. National Library of Medicine.Archivedfrom the original on 2016-04-25.Retrieved2016-04-16.
- ^"Understanding Blood Tests Online".Lab Tests Portal.Archived fromthe originalon 2016-04-09.Retrieved2016-04-16.
- ^Denny P, Hagen FK, Hardt M, et al. (May 2008)."The proteomes of human parotid and submandibular/sublingual gland salivas collected as the ductal secretions".J. Proteome Res.7(5): 1994–2006.doi:10.1021/pr700764j.PMC2839126.PMID18361515.
- ^"Microchip offers faster and cheaper way to test blood".CTV News.Bell Media. 2 February 2011.Archivedfrom the original on 3 October 2016.Retrieved2 October2016.
- ^Taylor, Kate (2011-03-18)."Blood analysis chip detects diseases in minutes".Archived fromthe originalon 2011-03-25.Retrieved2011-03-26.
- ^Dailey, Jessica (2011-03-22)."New SIMBAS Blood Analysis Biochip Can Diagnose Diseases In Minutes".Inhabitat.com.Archivedfrom the original on 2011-03-26.Retrieved2011-03-26.