# Situation: A 34-year-old man was diagnosed with human immunodeficiency virus (HIV) infection 1 week ago and has enrolled at a Department of Health (DOH)–accredited treatment hub, where he starts the once-daily tenofovir–lamivudine–dolutegravir (TLD) tablet today. His CD4 count is 150 cells/mm³, he has never had an opportunistic illness, and he has no drug allergies. How should the nurse classify the stage of his infection based on these data?

> source: MyMerci (mymerci.kr)  
> url: https://mymerci.kr/pages/nclex_q.php?qn_id=629721  
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> subject: Nursing Practice III — Care of Clients with Problems in Surgery, Oxygenation, Fluid and Electrolytes, Infectious, Inflammatory and Immunologic Response, Cellular Aberrations

## 문제

Situation: A 34-year-old man was diagnosed with human immunodeficiency virus (HIV) infection 1 week ago and has enrolled at a Department of Health (DOH)–accredited treatment hub, where he starts the once-daily tenofovir–lamivudine–dolutegravir (TLD) tablet today. His CD4 count is 150 cells/mm³, he has never had an opportunistic illness, and he has no drug allergies.

How should the nurse classify the stage of his infection based on these data?

## 보기

1. Not yet acquired immunodeficiency syndrome (AIDS), because he has never had an opportunistic illness
2. Acquired immunodeficiency syndrome (AIDS), stage 3, because his CD4 count is below 200 cells/mm³ **✔ 정답**
3. Not yet acquired immunodeficiency syndrome (AIDS), because the cutoff is a CD4 count below 100 cells/mm³
4. Acute HIV infection, not acquired immunodeficiency syndrome (AIDS), because he was diagnosed only 1 week ago

**정답: 2**

## 해설

Acquired immunodeficiency syndrome (AIDS), or stage 3 HIV infection, is defined by a CD4 count below 200 cells/mm³ OR an AIDS-defining illness. Either criterion is enough, so a count of 150 cells/mm³ classifies him as having AIDS even without an opportunistic illness. The date of diagnosis does not define the stage, because infection may have been present for years before testing.

## 심화 해설

Stage classification in HIV infection

HIV disease is staged by the degree of immune damage, not by how recently the diagnosis was made. The two accepted ways to define acquired immunodeficiency syndrome (AIDS), also called stage 3 HIV infection, are a CD4 count below 200 cells/mm³ or the presence of an AIDS-defining opportunistic illness. These criteria operate independently, so meeting either one is sufficient.

In this case, the CD4 count is 150 cells/mm³, which falls below the 200 cells/mm³ threshold. Even though the man has never had an opportunistic illness, the CD4 value alone places him in the AIDS category. The fact that he was diagnosed only 1 week ago does not change the staging, because HIV may have been present for years before testing. A person can therefore present with advanced immunosuppression at the time of first diagnosis.

Watch out! The cutoff is not 100 cells/mm³. A CD4 count below 200 cells/mm³ is the standard threshold for AIDS in the classification system used by the U.S. Centers for Disease Control and Prevention and in most licensure examination contexts. Some countries use different operational definitions for treatment eligibility, but that does not alter the staging definition being tested here.

The relationship between CD4 count and clinical outcomes supports why this threshold matters. In a cohort of 1,604 HIV-seropositive men followed over 10 years, lower CD4 lymphocyte counts were associated with a higher risk of HIV-associated neurologic complications such as dementia and sensory neuropathy [1]. This illustrates that CD4 depletion is not merely a laboratory number; it reflects meaningful immune compromise that increases vulnerability to serious disease. The CD4 count is therefore used as the primary marker of immunosuppression because it correlates with the risk of clinical deterioration.

A separate analysis reinforces that CD4-defined disease status remains central to clinical decision-making. In a study of HIV-infected individuals in Brazil, CD4 count was used as the reference marker for defining disease status, and hematologic and soluble adhesion molecule profiles were examined in relation to that CD4-based classification . Although Brazil applies a stricter public health threshold for AIDS (CD4 < 350 cells/mm³) than the WHO criterion (CD4 ≤ 200 cells/mm³), the underlying principle is the same: the CD4 count is the anchor for staging HIV disease and for determining the degree of immunosuppression. For licensure examination purposes, the widely used staging definition remains a CD4 count below 200 cells/mm³.

Key point! Staging is based on objective immunologic or clinical criteria, not on the date of diagnosis or the absence of symptoms. A patient with a CD4 count of 150 cells/mm³ has AIDS by laboratory criteria even if he feels well and has no opportunistic infection.

The role of CD4 testing in guiding care is also well established in resource-limited settings. In pregnant and postpartum women with HIV, CD4 cell count testing was more effective than clinical staging alone in identifying those eligible for antiretroviral therapy . This reinforces that CD4 count is a practical, objective tool for classifying disease severity and initiating treatment, which is exactly what this patient is beginning today with the once-daily tenofovir–lamivudine–dolutegravir (TLD) regimen.

The incorrect options can be ruled out systematically. Option 1 is wrong because an opportunistic illness is not required when the CD4 count is already below 200 cells/mm³. Option 3 is wrong because the threshold is 200 cells/mm³, not 100 cells/mm³. Option 4 is wrong because acute HIV infection refers to the early symptomatic phase soon after viral acquisition, and the timing of diagnosis does not override the immunologic staging criteria. The correct classification is AIDS, stage 3, based on the CD4 count of 150 cells/mm³.References (research sources)

- [1]Plasma viral load and CD4 lymphocytes predict HIV-associated dementia and sensory neuropathy.Research articleChilds EA, Lyles RH, Selnes OA, Chen B, Miller EN, Cohen BA (1999) · DOI: 10.1212/wnl.52.3.607

## 임상 시나리오

HIV Staging: CD4 Threshold Defines AIDSStage is based on immune damage, not time since diagnosis
AIDS, or stage 3 HIV infection, is diagnosed when the CD4 count falls below 200 cells/mm³ or an AIDS-defining illness is present. Either criterion alone is sufficient.

A CD4 count of 150 cells/mm³ meets the threshold for AIDS even without any opportunistic illness. Recent diagnosis does not change staging because infection may have been present for years before testing.

CautionThe cutoff is not 100 cells/mm³. Use 200 cells/mm³ as the standard threshold for AIDS classification in licensure and CDC-based contexts.

## 핵심 개념

- **AIDS** — Acquired immunodeficiency syndrome, also called stage 3 HIV infection, defined by a CD4 count below 200 cells/mm³ or an AIDS-defining illness.
- **CD4 count** — A laboratory measure of T-helper lymphocytes used to assess the degree of immune damage in HIV infection.
- **AIDS-defining illness** — An opportunistic infection or malignancy that indicates severe immunosuppression and independently establishes an AIDS diagnosis.
- **Stage 3 HIV** — The most advanced stage of HIV infection, synonymous with AIDS, marked by profound immunosuppression.
- **TLD** — A once-daily fixed-dose combination of tenofovir, lamivudine, and dolutegravir used for antiretroviral therapy.

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