Lower gastrointestinal bleeding laboratory findings: Difference between revisions

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Latest revision as of 19:38, 29 December 2017

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] ; Associate Editor(s)-in-Chief: Aditya Ganti M.B.B.S. [2]

Overview

The essential laboratory workup in the management of lower gastrointestinal bleeding includes a complete blood count, renal function test, liver function tests, and coagulation studies. In patients with life-threatening bleeding, although not diagnostic, a blood type and crossmatch should be done.

Laboratory Findings

Laboratory findings in patients presenting with lower gastrointestinal bleeding include:^[1]^[2]^[3]^[4]^[5]

Complete blood count

Complete blood count may show a low hemoglobin level or a drop from a previous baseline level.
In acute blood loss, the initial hemoglobin level may be normal but will fall with fluid resuscitation.
Other abnormalities, such as thrombocytopenia, may point to a variceal source of bleeding.
The presence of uremia or a history of aspirin or clopidogrel can significantly affect platelet function without causing thrombocytopenia.
Leukocytosis may point to an infectious or inflammatory cause.

Renal function tests

Abnormal values of renal function tests may indicate underlying kidney disease. Chronic kidney disease CKD is associated with increased risk for gastrointestinal bleeding by disrupting platelet function.
The presence of uremia may suggest bleeding is from an upper gastrointestinal source.
Intravenous contrast for angiograms must be administered with caution in patients with renal impairment to avoid the risk of contrast nephropathy.

Liver function tests

Patients with an underlying liver disease are at increased risk of gastrointestinal bleeding.
Bleeding will be more difficult to control due to coagulopathy associated with liver dysfunction. Hence LFT's are recommended to assess the severity of liver damage.
Abnormal liver function without any previous history of liver disease may suggest the presence of colorectal varices.

Coagulation studies

An elevated INR may indicate anticoagulation with warfarin or may be evidence of severe liver dysfunction.
A prolonged aPTT is seen in anticoagulation with heparin.

Blood type and cross match

Blood type and cross match identifies blood groups A, B, AB, O and Rhesus (Rh) factor.
Blood type and cross match is essential in the management of hemodynamically unstable patients who may need a blood transfusion.

Fecal Occult Blood Testing

Fecal occult blood test (FOBT's) have sufficient sensitivity to detect bleeding that is not visible in the stool.
Three types of FOBT are currently employed.
- Guaiac-based tests
- Heme-porphyrin tests
- Immuno-chemical tests

Types of FOBT	MOA	Causes of False-Positive
Guaiac-based tests Hemoccult II Hemoccult II SENSA	Pseudo-peroxidase activity of hemoglobin turns the guaiac compound blue in the presence of hydrogen peroxide.	Red meat consumption (nonhuman hemoglobin) Fruit consumption (cantaloupe, grapefruit, figs)
Heme-porphyrin tests HemeSelect FECA-EIA	HemoQuant, measures hemoglobin-derived porphyrins Allowing quantitative measurement of hemoglobin in stool	Extraintestinal blood loss Epistaxis Gingival bleeding Tonsillitis/pharyngitis Hemoptysis
Immuno-chemical tests	Detects intact human hemoglobin. Immunochemical FOBTs do not detect digested hemoglobin They are not able to detect bleeding from upper gastrointestinal sources	No false positives

Blood in stools

Abdominal pain

Yes

No

Fever

Rectal pain

Yes

No

H/O of constipation

No

Yes

No

Yes

Weightloss

Diverticulosis

Hemodynamic status

Diverticulitis

No

Yes

Stable

Unstable

Polyps

Colon cancer

Ischemic colitis

Stool culture

Positive

Negative

No

Yes

Infectious colitis

Inflammatory bowel disease

Weight Loss

Anal fissure
External Hemmrhoids

Yes

No

Rectal cancer
Colon cancer

Angiodysplasia
Polyps

References

↑ Tomizawa M, Shinozaki F, Hasegawa R, Shirai Y, Motoyoshi Y, Sugiyama T, Yamamoto S, Ishige N (2015). "Laboratory test variables useful for distinguishing upper from lower gastrointestinal bleeding". World J. Gastroenterol. 21 (20): 6246–51. doi:10.3748/wjg.v21.i20.6246. PMC 4445101. PMID 26034359.
↑ Moss AJ, Tuffaha H, Malik A (2016). "Lower GI bleeding: a review of current management, controversies and advances". Int J Colorectal Dis. 31 (2): 175–88. doi:10.1007/s00384-015-2400-x. PMID 26454431.
↑ Kim BS, Li BT, Engel A, Samra JS, Clarke S, Norton ID, Li AE (2014). "Diagnosis of gastrointestinal bleeding: A practical guide for clinicians". World J Gastrointest Pathophysiol. 5 (4): 467–78. doi:10.4291/wjgp.v5.i4.467. PMC 4231512. PMID 25400991.
↑ Strate LL, Gralnek IM (2016). "ACG Clinical Guideline: Management of Patients With Acute Lower Gastrointestinal Bleeding". Am. J. Gastroenterol. 111 (4): 459–74. doi:10.1038/ajg.2016.41. PMC 5099081. PMID 26925883.
↑ Beck DE, Margolin DA, Whitlow CB, Hammond KL (2007). "Evaluation and management of gastrointestinal bleeding". Ochsner J. 7 (3): 107–13. PMC 3096402. PMID 21603524.

Template:WH Template:WS

[pmid26034359-1] Tomizawa M, Shinozaki F, Hasegawa R, Shirai Y, Motoyoshi Y, Sugiyama T, Yamamoto S, Ishige N (2015). "Laboratory test variables useful for distinguishing upper from lower gastrointestinal bleeding". World J. Gastroenterol. 21 (20): 6246–51. doi:10.3748/wjg.v21.i20.6246. PMC 4445101. PMID 26034359.

[pmid26454431-2] Moss AJ, Tuffaha H, Malik A (2016). "Lower GI bleeding: a review of current management, controversies and advances". Int J Colorectal Dis. 31 (2): 175–88. doi:10.1007/s00384-015-2400-x. PMID 26454431.

[pmid25400991-3] Kim BS, Li BT, Engel A, Samra JS, Clarke S, Norton ID, Li AE (2014). "Diagnosis of gastrointestinal bleeding: A practical guide for clinicians". World J Gastrointest Pathophysiol. 5 (4): 467–78. doi:10.4291/wjgp.v5.i4.467. PMC 4231512. PMID 25400991.

[pmid26925883-4] Strate LL, Gralnek IM (2016). "ACG Clinical Guideline: Management of Patients With Acute Lower Gastrointestinal Bleeding". Am. J. Gastroenterol. 111 (4): 459–74. doi:10.1038/ajg.2016.41. PMC 5099081. PMID 26925883.

[pmid21603524-5] Beck DE, Margolin DA, Whitlow CB, Hammond KL (2007). "Evaluation and management of gastrointestinal bleeding". Ochsner J. 7 (3): 107–13. PMC 3096402. PMID 21603524.

[1]

[2]

[3]

[4]

[5]

@@ Line 4: / Line 4: @@
 ==Overview==
-An elevated/reduced concentration of serum/blood/urinary/CSF/other [lab test] is diagnostic of [disease name].
+The essential laboratory workup in the management of lower gastrointestinal bleeding includes a [[complete blood count]], [[Renal function tests|renal function]] test, [[liver function tests]], and [[coagulation studies]]. In patients with life-threatening bleeding, although not diagnostic, a [[Blood types|blood type]] and [[Crossmatching|crossmatch]] should be done.
-OR
+==Laboratory Findings==
+Laboratory findings in patients presenting with lower  gastrointestinal bleeding include:<ref name="pmid26034359">{{cite journal |vauthors=Tomizawa M, Shinozaki F, Hasegawa R, Shirai Y, Motoyoshi Y, Sugiyama T, Yamamoto S, Ishige N |title=Laboratory test variables useful for distinguishing upper from lower gastrointestinal bleeding |journal=World J. Gastroenterol. |volume=21 |issue=20 |pages=6246–51 |year=2015 |pmid=26034359 |pmc=4445101 |doi=10.3748/wjg.v21.i20.6246 |url=}}</ref><ref name="pmid26454431">{{cite journal |vauthors=Moss AJ, Tuffaha H, Malik A |title=Lower GI bleeding: a review of current management, controversies and advances |journal=Int J Colorectal Dis |volume=31 |issue=2 |pages=175–88 |year=2016 |pmid=26454431 |doi=10.1007/s00384-015-2400-x |url=}}</ref><ref name="pmid25400991">{{cite journal |vauthors=Kim BS, Li BT, Engel A, Samra JS, Clarke S, Norton ID, Li AE |title=Diagnosis of gastrointestinal bleeding: A practical guide for clinicians |journal=World J Gastrointest Pathophysiol |volume=5 |issue=4 |pages=467–78 |year=2014 |pmid=25400991 |pmc=4231512 |doi=10.4291/wjgp.v5.i4.467 |url=}}</ref><ref name="pmid26925883">{{cite journal |vauthors=Strate LL, Gralnek IM |title=ACG Clinical Guideline: Management of Patients With Acute Lower Gastrointestinal Bleeding |journal=Am. J. Gastroenterol. |volume=111 |issue=4 |pages=459–74 |year=2016 |pmid=26925883 |pmc=5099081 |doi=10.1038/ajg.2016.41 |url=}}</ref><ref name="pmid21603524">{{cite journal |vauthors=Beck DE, Margolin DA, Whitlow CB, Hammond KL |title=Evaluation and management of gastrointestinal bleeding |journal=Ochsner J |volume=7 |issue=3 |pages=107–13 |year=2007 |pmid=21603524 |pmc=3096402 |doi= |url=}}</ref>
+===[[Complete blood count]]===
+*[[Complete blood count]] may show a [[Anemia|low hemoglobin level]] or a drop from a previous baseline level.
+*In acute blood loss, the initial [[hemoglobin]] level may be normal but will fall with fluid resuscitation.
+*Other abnormalities, such as [[thrombocytopenia]], may point to a variceal source of bleeding.
+*The presence of [[uremia]] or a history of [[aspirin]] or [[clopidogrel]] can significantly affect [[platelet]] function without causing [[thrombocytopenia]].
+*[[Leukocytosis]] may point to an [[infectious]] or [[inflammatory]] cause.
-Laboratory findings consistent with the diagnosis of [disease name] include [abnormal test 1], [abnormal test 2], and [abnormal test 3].
+===[[Renal function tests]]===
+*Abnormal values of [[renal function tests]] may indicate underlying [[kidney disease]]. Chronic kidney disease [[CKD]] is associated with increased risk for gastrointestinal bleeding by disrupting [[platelet]] function.
-OR
+*The presence of [[uremia]] may suggest bleeding is from an upper gastrointestinal source.
+*Intravenous contrast for [[Angiogram|angiograms]] must be administered with caution in patients with [[renal]] impairment to avoid the risk of [[Contrast induced nephropathy|contrast nephropathy]].
-[Test] is usually normal among patients with [disease name].
+===[[Liver function tests]]===
+*Patients with an underlying [[Liver diseases|liver disease]] are at increased risk of gastrointestinal bleeding.
-OR
+*[[Bleeding]] will be more difficult to control due to [[coagulopathy]] associated with liver dysfunction. Hence [[Liver function tests|LFT's]] are recommended to assess the severity of liver damage.
+*Abnormal liver function without any previous history of liver disease may suggest the presence of [[colorectal]] [[varices]].
-Some patients with [disease name] may have elevated/reduced concentration of [test], which is usually suggestive of [progression/complication].
+===Coagulation studies===
+*An elevated [[INR]] may indicate [[Anticoagulation therapy|anticoagulation]] with [[warfarin]] or may be evidence of severe liver dysfunction.
-OR
+*A prolonged [[aPTT]] is seen in [[anticoagulation]] with [[heparin]].
+===Blood type and cross match===
-There are no diagnostic laboratory findings associated with [disease name].
+*Blood type and cross match identifies [[blood groups]] A, B, AB, O and [[Rhesus factor|Rhesus (Rh) factor]].
+*Blood type and cross match is essential in the management of hemodynamically unstable patients who may need a [[blood transfusion]].
-==Laboratory Findings==
+===Fecal Occult Blood Testing===
+*Fecal occult blood test ([[FOBT|FOBT's]]) have sufficient sensitivity to detect bleeding that is not visible in the stool.
+*Three types of FOBT are currently employed.
+**Guaiac-based tests
+**Heme-porphyrin tests
+**Immuno-chemical tests
+{| class="wikitable"
+!Types of FOBT
+!MOA
+!Causes of False-Positive
+|-
+|
+* Guaiac-based tests
+** Hemoccult II
+** Hemoccult II SENSA
+|
+* Pseudo-peroxidase activity of [[hemoglobin]] turns the guaiac compound blue in the presence of [[hydrogen peroxide]].
+|
+* Red meat consumption (nonhuman [[hemoglobin]])
-*There are no diagnostic laboratory findings associated with [disease name].
+* Fruit consumption (cantaloupe, grapefruit, figs)
-OR
+|-
-*An elevated/reduced concentration of serum/blood/urinary/CSF/other [lab test] is diagnostic of [disease name].
+|
-*[Test] is usually normal among patients with [disease name].
+* Heme-porphyrin tests
-*Laboratory findings consistent with the diagnosis of [disease name] include:
+** HemeSelect
-**[Abnormal test 1]
+** FECA-EIA
-**[Abnormal test 2]
+|
-**[Abnormal test 3]
+*HemoQuant, measures [[hemoglobin]]-derived [[porphyrins]]
+*Allowing quantitative measurement of [[hemoglobin]] in stool
+|
+* Extraintestinal blood loss
+** [[Epistaxis]]
+** [[Gingival bleeding]]
+** [[Tonsillitis]]/[[pharyngitis]]
+** [[Hemoptysis]]
+|-
+|
+* Immuno-chemical tests
+|
+* Detects intact human [[hemoglobin]].
+* Immunochemical [[FOBT|FOBTs]] do not detect digested [[hemoglobin]]
+* They are not able to detect bleeding from upper gastrointestinal sources
-*Some patients with [disease name] may have elevated/reduced concentration of [test], which is usually suggestive of [progression/complication].
+|
+* No false positives
+|}
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+{{familytree | | | | | | | | | | |,|-|-|-|-|^|-|-|-|.| | | | | | | | | B01 | | | | | | B02 | |!|B01=No|B02=Yes|}}
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+{{familytree | | | | | | T01 | | | | | | T02 | | | | | | | | | E01 | | | | | | E02 | | | | | |!|T01=Stable|T02=Unstable|E01=Polyps|E02=Colon cancer}}
+{{familytree | | | | | | |!| | | | | | | |!| | | | | | | | | | | | | | | | | | | | | | | | | |!|}}
+{{familytree | | | | | | |!| | | | | | | A01 | | | | | | | | | | | | | | | | | | | | |,|-|-|-|'|A01=Ischemic colitis}}
+{{familytree | | | | | | B01 | | | | | | | | | | | | | | | | | | | | | | | | | | | | |!| | | | |B01=Stool culture}}
+{{familytree | | |,|-|-|-|^|-|-|-|-|.| | | | | | | | | | | | | | | | | | | | |,|-|-|-|^|-|-|-|-|.|}}
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+{{familytree | | | | | | | | | | | | | | | | | | | | | | | | | | | |,|-|-|-|-|^|-|-|-|-|.| |}}
+{{familytree | | | | | | | | | | | | | | | | | | | | | | | | | | | |!| | | | | | | | | |!| }}
+{{familytree | | | | | | | | | | | | | | | | | | | | | | | | | | | C03 | | | | | | | | C04 |C03=Yes|C04=No|}}
+{{familytree | | | | | | | | | | | | | | | | | | | | | | | | | | | |!| | | | | | | | | |!| | }}
+{{familytree | | | | | | | | | | | | | | | | | | | | | | | | | | | D01 | | | | | | | | D02 |D01=Rectal cancer<br>Colon cancer|D02=Angiodysplasia<br>Polyps }}
+{{familytree/end}}
+</div>
+</small>
 ==References==