Angiotensin Converting Enzyme

Angiotensin Converting Enzyme

Angiotensin converting enzyme (ACE) participates in the renin cascade in response to hypovolemia, by converting angiotensinogen I to angiotensinogen II. The latter hormone is a potent vasoconstrictor that increases blood pressure.Angiotensin converting enzyme (ACE) participates in the renin cascade in response to hypovolemia. Its peptidase action on the decapeptide angiotensinogen I results in the hydrolysis of a terminal histadyl lucine dipeptide and the formation of the octapeptide angiotensin II, a potent vasoconstrictor that increases blood pressure.The primary source of ACE is the endothelium of the lung.

Fact File

• The endothelium of the lung is the primary source of ACE. Because of this location, ACE production is increased in sarcoidosis. Serum ACE concentration is elevated in 79% of patients with active sarcoidosis.
• ACE activity reflects disease activity. Levels are higher in stage III than in stage 1 disease.
• Enzyme activity decreases dramatically in some patients after prednisone therapy.
• Other diseases such as Gaucher's disease, leprosy, histoplasmosis, amyloidosis, untreated hyperthyroidism, psoriasis and chronic renal disease have also been associated with increased ACE levels.
• Serum ACE is significantly decreased in patients taking ACE inhibitors such as Vasotec and captopril.
• Corticosteroids may slightly decrease ACE values.

Adult reference range is 7 to 46 U/L. Children and adolescents normally have values as much as 50% higher.
Specimen requirement is one red top or SST tube of blood. Lavender top tubes should not be used because EDTA inhibits the enzyme.

Specimen TypeSerum

Specimen RequiredContainer/Tube:Plain, red-top tube(s) or serum gel tube(s)

Specimen Volume:2 mL of serum

Collection Instructions:Send specimen in plastic vial.

Note:The use of angiotensin converting enzyme (ACE)-inhibiting antihypertensive drugs will cause decreased ACE values.

Reject Due To

Specimens other thanSerum

HemolysisMild reject; Gross reject

LipemiaMild OK; Gross reject

IctericMild reject; Gross reject

Transport Temperature Frozen\RefrigOK\Ambient<1dayOK

Reference

• Miyoshi S, Hamada H, Kadowaki T, Hamaguchi N, Ito R, Irifune K, Higaki J.Comparative evaluation of serum markers in pulmonarysarcoidosis.Chest. 2010 Jun;137(6):1391-7. Epub 2010 Jan 15.

• Turton CW, Grundy E, Firth G, Mitchell D, Rigden BG, Turner-Warwick M.Value of measuring serum angiotensin I converting enzyme and serum lysozyme in the management of sarcoidosis.Thorax. 1979 Feb;34(1):57-62.

• Studdy PR, Bird R, Neville E, James DG.Biochemical findings in sarcoidosis.J Clin Pathol. 1980 Jun;33(6):528-33.

• P R Studdy, R Lapworth, and R BirdAngiotensin-converting enzyme and its clinical significance--a review.J Clin Pathol.1983 August;36(8): 938–947.