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The first automated random-access analyser. When introduced by DuPont Chemical Diagnostics division in 1968, the aca had a menu of 8 tests; the current generation has a menu of more than 100.


Abbreviation for:
acute cutaneous anaphylaxis
acquired child aphasia
acrodermatitis chronica atrophicans
acute cerebellar ataxia
adenylyl cyclase A
adrenal cortex autoantibodies
aminocaproic acid
anterior cerebral artery
anterior communicating artery
anti-cardiolipin antibody
anti-centromere antibody
Area Cost Adjustment (Medspeak-UK)
Segen's Medical Dictionary. © 2012 Farlex, Inc. All rights reserved.


Lab medicine The very first automated random-access analyzer. See Random access analyzer.
McGraw-Hill Concise Dictionary of Modern Medicine. © 2002 by The McGraw-Hill Companies, Inc.

Antibodies, Cardiolipin, Immunoglobulin A, Immunoglobulin G, and Immunoglobulin M

Synonym/acronym: Antiphospholipid antibody, lupus anticoagulant, LA, ACA.

Common use

To detect the presence of antiphospholipid antibodies, which can lead to the development of blood vessel problems and complications including stroke, heart attack, and miscarriage.


Serum (1 mL) collected in a red-top tube.

Normal findings

(Method: Immunoassay, enzyme-linked immunosorbent assay [ELIS])
IgA (APL = 1 unit IgA phospholipid)IgG (GPL = 1 unit IgG phospholipid)IgM (MPL = 1 unit IgM phospholipid)
Negative: 0–11 APLNegative: 0–14 GPLNegative: 0–12 MPL
Indeterminate: 12–19 APLIndeterminate: 15–19 GPLIndeterminate: 13–19 MPL
Low-medium positive: 20–80 APLLow-medium positive: 20–80 GPLLow-medium positive: 20–80 MPL
Positive: Greater than 80 APLPositive: Greater than 80 GPLGreater than 80 MPL


Anticardiolipin (ACA) is one of several identified antiphospholipid antibodies. ACAs are of IgG, IgM, and IgA subtypes, which react with proteins in the blood that are bound to phospholipid and interfere with normal blood vessel function. The two primary types of problems they cause are narrowing and irregularity of the blood vessels and blood clots in the blood vessels. ACAs are found in individuals with lupus erythematosus, lupus-related conditions, infectious diseases, drug reactions, and sometimes fetal loss. ACAs are often found in association with lupus anticoagulant. Increased antiphospholipid antibody levels have been found in pregnant women with lupus who have had miscarriages. β2 Glycoprotein 1, or apolipoprotein H, is an important facilitator in the binding of antiphospholipid antibodies like ACA. A normal level of β2 glycoprotein 1 is 19 units or less when measured by ELISA assays. β2Glycoprotein 1 measurements are considered to be more specific than ACA because they do not demonstrate nonspecific reactivity as do ACA in sera of patients with syphilis or other infectious diseases. The combination of noninflammatory thrombosis of blood vessels, low platelet count, and history of miscarriage is termed antiphospholipid antibody syndrome and is documented as present if at least one of the clinical and one of the laboratory criteria are met.

Clinical criteria

  • Vascular thrombosis confirmed by histopathology or imaging studies
  • Pregnancy morbidity defined as either one or more unexplained deaths of a morphologically normal fetus at or beyond the 10th week of gestation
  • One or more premature births of a morphologically normal neonate before the 34th week of gestation due to eclampsia or severe pre-eclampsia
  • Three or more unexplained consecutive spontaneous abortions before the 10th week of gestation

Laboratory criteria (all measured by a standardized ELISA, according to recommended procedures)

  • ACA IgG, or IgM, detectable at greater than 40 units on two or more occasions at least 12 wk apart
  • Lupus anticoagulant (LA) detectable on two or more occasions at least 12 wk apart
  • Anti-β2glycoprotein 1 antibody, IgG, or IgM detectable on two or more occasions at least 12 wk apart

This procedure is contraindicated for



  • Assist in the diagnosis of antiphospholipid antibody syndrome

Potential diagnosis

Increased in

  • While ACAs are observed in specific diseases, the exact mechanism of these antibodies in disease is unclear. In fact, the production of ACA can be induced by bacterial, treponemal, and viral infections. Development of ACA under this circumstance is transient and not associated with an increased risk of antiphospholipid antibody syndrome. Patients who initially demonstrate positive ACA levels should be retested after 6 to 8 wk to rule out transient antibodies that are usually of no clinical significance.

  • Antiphospholipid antibody syndrome
  • Chorea
  • Drug reactions
  • Epilepsy
  • Infectious diseases
  • Mitral valve endocarditis
  • Patients with lupuslike symptoms (often antinuclear antibody–negative)
  • Placental infarction
  • Recurrent fetal loss (strong association with two or more occurrences)
  • Recurrent venous and arterial thromboses
  • SLE

Decreased in


Critical findings


Interfering factors

  • Drugs that may increase anticardiolipin antibody levels include chlorpromazine, penicillin, procainamide, phenytoin, and quinidine.
  • Cardiolipin antibody is partially cross-reactive with syphilis reagin antibody and lupus anticoagulant. False-positive rapid plasma reagin results may occur.

Nursing Implications and Procedure

Potential nursing problems

ProblemSigns and SymptomsInterventions
Fear (Related to possible loss of potential child; disability; death)Verbalization of fear; restlessness; increased tension; continuous questioning; increased blood pressure, heart rate, respiratory rateProvide specific and culturally appropriate education; assist the patient and family to recognize effective coping strategies; assist the patient to acknowledge fear; provide a safe environment to decrease fear; explore cultural influences that may enhance fear; utilize therapeutic touch as appropriate to decrease fear; collaborate with social services to address specific medical problems associated with fear
Grief (Related to placental infarction associated with placental cell death resulting in loss of potential child)Apparent psychological and emotional distress; withdrawal; detachment; loss of appetite; refusal to participate in activities of daily living; anger; blame Assess decision-making ability; encourage expression of grief; provide contact information for grief support group; assist to identify current support group; provide social services referral as appropriate; allow the patient to recall the loss and express feelings
Spirituality (Related to significant loss; fear of death; debilitation disease process)Forgiveness; acceptance; anger at spiritual leaders; expressed feelings of hopeless, powerlessness; abandonment; refusals or inability to participate in spiritual activities (prayer); expresses feelings over lack of meaning with life or serenity Encourage the verbalization of feelings in a safe nonjudgmental environment; assess the desire for contact from associated spiritual leader; foster a supportive relationship with the patient and family; encourage a display of objects (spiritual, religious) that provide emotional relief; asses for expressions of hope
Family process (Related to altered role performance secondary to disease progression)Inability to perform in supportive family role; alteration in family finances; change in communication patterns; change in the assignment of family tasks and the performance of those tasks; alterations in intimacy Family counseling; facilitating opportunities for the patient and family to express their feelings; assess the patient and family perception of the problems; evaluate patient and family weaknesses, strengths, and coping strategies; help the family and patient break down concerns into manageable parts


  • Positively identify the patient using at least two unique identifiers before providing care, treatment, or services.
  • Patient Teaching: Inform the patient this test can assist in evaluating the amount of potentially harmful circulating antibodies.
  • Obtain a history of the patient’s complaints, including a list of known allergens, especially allergies or sensitivities to latex.
  • Obtain a history of the patient’s hematopoietic, immune, and reproductive systems; symptoms; and results of previously performed laboratory tests and diagnostic and surgical procedures.
  • Obtain a list of the patient’s current medications, including herbs, nutritional supplements, and nutraceuticals (see Effects of Natural Products on Laboratory Values online at DavisPlus).
  • Review the procedure with the patient. Inform the patient that specimen collection takes approximately 5 to 10 min. Address concerns about pain and explain that there may be some discomfort during the venipuncture.
  • Sensitivity to social and cultural issues, as well as concern for modesty, is important in providing psychological support before, during, and after the procedure.
  • Note that there are no food, fluid, or medication restrictions unless by medical direction.


  • Potential complications: N/A
  • Avoid the use of equipment containing latex if the patient has a history of allergic reaction to latex.
  • Instruct the patient to cooperate fully and to follow directions. Direct the patient to breathe normally and to avoid unnecessary movement.
  • Observe standard precautions, and follow the general guidelines in Patient Preparation and Specimen Collection. Positively identify the patient, and label the appropriate specimen container with the corresponding patient demographics, initials of the person collecting the specimen, date, and time of collection. Perform a venipuncture.
  • Remove the needle and apply direct pressure with dry gauze to stop bleeding. Observe/assess venipuncture site for bleeding or hematoma formation and secure gauze with adhesive bandage.
  • Promptly transport the specimen to the laboratory for processing and analysis.


  • Inform the patient that a report of the results will be made available to the requesting health-care provider (HCP), who will discuss the results with the patient.
  • Recognize anxiety related to test results, and be supportive of fear of shortened life expectancy. Discuss the implications of abnormal test results on the patient’s lifestyle. Provide teaching and information regarding the clinical implications of the test results, as appropriate. Educate the patient regarding access to counseling services. Provide contact information, if desired, for the Lupus Foundation of America (
  • Depending on the results of this procedure, additional testing may be performed to evaluate or monitor progression of the disease process and determine the need for a change in therapy. Evaluate test results in relation to the patient’s symptoms and other tests performed.
  • Patient Education

    • Reinforce information given by the patient’s HCP regarding further testing, treatment, or referral to another HCP.
    • Answer any questions or address any concerns voiced by the patient or family.
  • Expected Patient Outcomes

    • Knowledge
    • States understanding that fetal loss may be associated with placental infarct.
    • States understanding of the importance in identifying a support system that can assist with coping with the spiritual distress of grief and loss.
    • Skills
    • Attends recommended grief counseling for emotional and psychological support related to fetal loss.
    • Actively participates in the provision of self-care associated with the activities of daily living.
    • Attitude
    • Seeks assistance from spiritual leader to relieve emotional distress associated with loss of potential child, or loss of function secondary to disease process.
    • Agrees to listen to the designated spiritual leader to assist in decreasing grief, loss.

Related Monographs

  • Related tests include ANA, CBC, CBC platelet count, fibrinogen, lupus anticoagulant antibodies, protein C, protein S, and syphilis serology.
  • See the Hematopoietic, Immune, and Reproductive systems tables at the end of the book for related tests by body system.
Handbook of Laboratory and Diagnostic Tests, © 2013 Farlex and Partners

Patient discussion about aca

Q. What is the difference between alcoholism, alcohol abuse and alcohol dependent?

A. Alcoholism is the high carve for drinking without caring for negative results it will have on physical, mental, emotional and social life. A binge drinker who continues to drink even though the problem has started in his normal life will lead to alcohol abuse and he may start the journey for alcoholism. In alcohol dependence the drinker steps up from the alcohol abuse and the crave increases in spite of the biggest problem on head. We can say that alcohol dependence is alcoholism.

Q. My son who is an alcohol abuse is undergoing treatment? My son who is an alcohol abuse is undergoing treatment. He stops his medicines in the middle of the treatment and restart taking alcohol. Doctor had warned to stop consuming alcohol in excess. With heavy drink he comes late at night and it frightens me. He drinks alcohol very badly and behaves violent also. He says he cannot stop. I am getting worried and was finding some information about the harm effects the excess drinking can bring to him?

A. A) He must stop or reduce alcohol now. Allow him to drink in house so that he can be safe from some other dangerous situations which can mess his life. Once in home you can deal him well. At least you can make him to have his medicines. The adverse effects of alcohol consumption are liver damage, anemia, nerve damage, and pancreatitis. These can ruin his life.

Q. Does alcohol drinking act as a catalyst of a problem? Does alcohol drinking act as a catalyst of a problem? My father has been battling depression and anxiety for many years and he used to drink in the past. Recently his behavior associated with drinking is visible and I strongly suspect that he is drinking again. Generally we get silly after drinking but my dad`s perception are altered in a negative way….

A. Yes that’s true… when I drink my depression gets amplified. And this almost happens on the issues which hurts me. Sometimes it becomes self destructive. One should even look that it doesn’t harm anyone. Keep him under observation for 3 days and if the problem persists, then you must take him to a doctor.

More discussions about aca
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