Editing Priapism (section)

=== Laboratory ===

* '''<span style="color:#ff0000">Corporal blood gas by aspiration</span>'''
** '''<span style="color:#ff0000">Should be obtained in the emergency evaluation of priapism</span>[https://pubmed.ncbi.nlm.nih.gov/35536142/ ★]'''
***Clinical situations where a blood gas may be omitted at the clinician’s discretion (3):
***#Priapism induced by in-office or at home ICI therapies
***#Cases of recurrent ischemic priapism (i.e., SCD)
***#When the diagnosis is abundantly clear by history and examination alone
**Most common diagnostic methods of distinguishing acute ischemic priapism from non-ischemic priapism when the diagnosis cannot be made by history alone
**Blood aspirated from the corpus cavernosum in patients with acute ischemic priapism is hypoxic (dark red), while corporal blood in NIP patients is normally oxygenated (bright red)

{| class="wikitable"
!Source
!<span style="color:#ff0000">PO2 (mm Hg)</span>
!<span style="color:#ff0000">PCO2 (mm Hg)</span>
!<span style="color:#ff0000">pH</span>
|-
!Normal arterial blood (room air)
|'''>90'''
|'''<40'''
|'''7.40'''
|-
!Normal mixed venous blood (room air)
|40
|50
|7.35
|-
!<span style="color:#ff0000">Ischemic priapism (first corporal aspirate)</span>
|<span style="color:#ff0000">'''<30'''</span>
|<span style="color:#ff0000">'''>60'''</span>
|<span style="color:#ff0000">'''<7.25'''</span>
|}

* '''CBC'''
** May identify elevated white blood cell counts, potentially identifying cases where priapism is due to underlying malignancy (e.g., leukemia).  
**Among men with sickle cell disease, acute ischemic priapism is associated with lower hemoglobin and elevated lactate dehydrogenase, bilirubin, aspartate aminotransferase, reticulocyte count, white blood cells, and platelet counts. 
**Platelet and eosinophil counts may also be elevated in men with acute ischemic priapism. 
* '''Hemoglobin electrophoresis and other sickle cell testing'''
** '''May be appropriate in select clinical scenarios and based on underlying clinical suspicion (e.g., patient race)'''
***In most cases, most men with sickle cell disease have been diagnosed previously.  
****The yield of identifying men with previously undiagnosed SCD among a cohort of men presenting with priapism is not well established.  
*'''Urine and serum toxicology panels'''
** A thorough medication and social history may provide enough information to determine the underlying cause of the priapism without collection of these studies.
***Testing for potential substances may have a high rate of false negativity, particularly with synthetic and otherwise altered versions of common illicit substances
*'''While CBC, hemoglobin electrophoresis, and toxicology panels may contribute to the identification of underlying cause, they often will not be used to guide treatment of the acute presentation'''